Reduce height of toggle on expanded view source event

[luixxiul]

Closes https://github.com/vector-im/element-web/issues/22873

This PR reduces height of clickable toggle area on expanded view source event.

Before	After

Signed-off-by: Suguru Hirahara [email protected]

type: defect

Checklist

• [x] Tests written for new code (and old code if feasible)
• [x] Linter and other CI checks pass
• [x] Sign-off given on the changes (see CONTRIBUTING.md)

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Here's what your changelog entry will look like:

🐛 Bug Fixes

• Reduce height of toggle on expanded view source event (#9067). Fixes vector-im/element-web#22873. Contributed by @luixxiul.