feat: ScrollableShadows component

[benjackwhite]

Problem

Working on adding vertical scrollers on a different feature and decided it would make sense to make a proper component here

Changes

• Adds the ScrollableShadows component
• Replaces uses of the other "scrollable" stuff
• Improves the useScrollable to not fire if there is no change
• Adds it to the 3000 navbar
• NOTE: Wanted to add it to the Panel tab list but couldn't figure out all the weirdness around the transforming stuff...

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[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

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[github-actions]

Size Change: +16 B (0%)

Total Size: 1.99 MB

ℹ️ View Unchanged

Filename	Size	Change
frontend/dist/toolbar.js	1.99 MB	+16 B (0%)

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