Add test to check block start padding of a continued event tile on modern/group layout

[luixxiul]

For https://github.com/matrix-org/matrix-react-sdk/pull/9033

This PR adds a test to check whether block start padding of a continued event tile on modern/group layout is set to zero without !important flag.

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

type: task

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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This change is marked as an internal change (Task), so will not be included in the changelog.

[andybalaam]

Please could you resolve the conflicts and then ping me to merge?