refactor(frontend): remove stale reload method call on /admin/users page

[zyoshoka]

What

/admin/users ページに残っている不要なメソッド呼び出しを削除します。

Why

5c5d3c1#diff-2ef64414b49d081dda4ce08eeced24033bcf5e4f36091700964a89b43be1fcc6L39-R39 の際に書き換え変え忘れたからか、入力欄を更新した際にコンソールに次のようなエラーが出るようになっている上に、別になくても更新されるため

[Vue warn]: Error in https://vuejs.org/error-reference/#runtime-6: "TypeError: can't access property "reload", i.$refs.users is undefined"

Additional info (optional)

Checklist

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

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 20.25%. Comparing base (41936c1) to head (0b804c7).
Report is 1 commits behind head on develop.

Files	Patch %	Lines
packages/frontend/src/pages/admin/users.vue	0.00%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           develop   #14406       +/-   ##
============================================
- Coverage    39.91%   20.25%   -19.67%     
============================================
  Files         1545      723      -822     
  Lines       190505   100283    -90222     
  Branches      2654     1049     -1605     
============================================
- Hits         76046    20308    -55738     
+ Misses      113898    79434    -34464     
+ Partials       561      541       -20     

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[syuilo]

🙏🏻