feat(billing): subscribe to all products (client side)

[zlwaterfield]

See: https://github.com/PostHog/billing/pull/676

This PR is adding the UI changes for subscribe to all products. More details on the overall project in the PR linked above. The surface area for billing includes billing page, page gates and onboarding billing steps - so those are the areas this code will change.

As you can see it uses a mixture of the SUBSCRIBE_TO_ALL_PRODUCTS ff + the subscription_level to determine what experience to show. How the logic works

• if they have the SUBSCRIBE_TO_ALL_PRODUCTS ff
  • if they have free / paid subscription_level then use the new experiences
  • else default to existing experience (because we don't want to change people who are partially subscribed until we backfill)
• else default to existing experience

The core changes:

• add a feature flag that allows this to be rolled out over time
• keep the experience the same for existing users who have a subscription
• aligning terminology in the new experiences
  • free <> paid -> upgrade / downgrade
  • addon -> add / remove
  • no usage for subscribe/unsubscribe
• mild UI and spacing improvements to the billing page

Note: this does not yet include the changes to the onboarding plan comparison showing all products

There is an intentional focus on not changing the experience for existing users.

Further notes:

• the use of has_active_subscription will probably be migrated to use subscription_level in the future
• there's some UX issues around the pay gate upgrade loading - need to look into.

Other PRs before this one to help make the changes simpler:

• chore: remove pay gate page #22931
• chore: remove subscribe from paygate experiment #22956
• chore: updating /activation endpoint to /activate #22779
• feat: better billing limits UI #22726
• chore: updating activation endpoint to be activate #22719
• https://github.com/PostHog/billing/pull/707
• https://github.com/PostHog/billing/pull/708

[posthog-bot]

📸 UI snapshots have been updated

7 snapshot changes in total. 0 added, 7 modified, 0 deleted:

• chromium: 0 added, 7 modified, 0 deleted (diff for shard 1, diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

7 snapshot changes in total. 0 added, 7 modified, 0 deleted:

• chromium: 0 added, 7 modified, 0 deleted (diff for shard 1, diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

13 snapshot changes in total. 0 added, 13 modified, 0 deleted:

• chromium: 0 added, 13 modified, 0 deleted (diff for shard 1, diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

11 snapshot changes in total. 0 added, 11 modified, 0 deleted:

• chromium: 0 added, 11 modified, 0 deleted (diff for shard 1, diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

2 snapshot changes in total. 0 added, 2 modified, 0 deleted:

• chromium: 0 added, 2 modified, 0 deleted (diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

1 snapshot changes in total. 0 added, 1 modified, 0 deleted:

• chromium: 0 added, 1 modified, 0 deleted (diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

2 snapshot changes in total. 0 added, 2 modified, 0 deleted:

• chromium: 0 added, 2 modified, 0 deleted (diff for shard 1)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

1 snapshot changes in total. 0 added, 1 modified, 0 deleted:

• chromium: 0 added, 1 modified, 0 deleted (diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

2 snapshot changes in total. 0 added, 2 modified, 0 deleted:

• chromium: 0 added, 2 modified, 0 deleted (diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

3 snapshot changes in total. 0 added, 3 modified, 0 deleted:

• chromium: 0 added, 3 modified, 0 deleted (diff for shard 1, diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

1 snapshot changes in total. 0 added, 1 modified, 0 deleted:

• chromium: 0 added, 1 modified, 0 deleted (diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

1 snapshot changes in total. 0 added, 1 modified, 0 deleted:

• chromium: 0 added, 1 modified, 0 deleted (diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[posthog-bot]

📸 UI snapshots have been updated

2 snapshot changes in total. 0 added, 2 modified, 0 deleted:

• chromium: 0 added, 2 modified, 0 deleted (diff for shard 2)
• webkit: 0 added, 0 modified, 0 deleted

Triggered by this commit.

👉 Review this PR's diff of snapshots.

[raquelmsmith]

Test failures here are not related to this PR so going to push it out