fix(frontend): ユーザーリストのバナー画像をプロキシを通すように

[kakkokari-gtyih]

What

Why

Fix #14450

Additional info (optional)

gif画像が通り、画像の縮小にも対応しているプロキシモードはavatarだったのでそれを使用した

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

[syuilo]

うーーーむ bannerなのにavatar指定なのは違和感あるわね

[kakkokari-gtyih]

bannerなのにavatar指定なのは違和感あるわね

それは思ったけどproxyを外部化している場合はそちらの改修も必要になるのでどうしよう・・・

[kakkokari-gtyih]

ユーザーリストではgifなバナー画像が動かない仕様にするのでも良いかも

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 20.02%. Comparing base (043ab1f) to head (ddb932b). Report is 1 commits behind head on develop.

Files	Patch %	Lines
packages/frontend/src/components/MkUserInfo.vue	0.00%	2 Missing :warning:
packages/frontend/src/components/MkUserPopup.vue	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #14454 +/- ## ============================================ - Coverage 39.89% 20.02% -19.87% ============================================ Files 1547 725 -822 Lines 190970 100535 -90435 Branches 3519 1052 -2467 ============================================ - Hits 76190 20136 -56054 + Misses 114187 79855 -34332 + Partials 593 544 -49 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.