fix(frontend): 絵文字関連のスタイルが崩れているのを修正

[kakkokari-gtyih]

What

変更のビフォーアフターは https://github.com/MisskeyIO/misskey/pull/725 を参照のこと

Why

Fix #12965

Additional info (optional)

Checklist

• [x] Read the contribution guide
• [ ] Test working in a local environment
• [ ] (If needed) Add story of storybook
• [x] (If needed) Update CHANGELOG.md
• [ ] (If possible) Add tests

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 37.50000% with 5 lines in your changes missing coverage. Please review.

Project coverage is 19.55%. Comparing base (0e4b6d1) to head (e952ae5). Report is 3 commits behind head on develop.

Files with missing lines	Patch %	Lines
...ackages/frontend/src/components/MkNotification.vue	0.00%	2 Missing :warning:
...kages/frontend/src/pages/custom-emojis-manager.vue	0.00%	2 Missing :warning:
...ages/frontend/src/components/MkReactionTooltip.vue	0.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #14559 +/- ## ======================================== Coverage 19.54% 19.55% ======================================== Files 713 713 Lines 100312 100317 +5 Branches 997 997 ======================================== + Hits 19610 19612 +2 - Misses 80158 80161 +3 Partials 544 544 ```

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[syuilo]

🙏🏿