chore(data-warehouse): restore form

[EDsCODE]

Problem

• onboarding panel links to the wrong form

Changes

• bring back the external data form and make sure links are correct

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[posthog-bot]

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[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

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