feat: add name existence check before creating attachment group and storage policy

[LEIYOUSU]

What type of PR is this?

/area ui
/kind improvement
/milestone 2.20.x

What this PR does / why we need it:

在创建附件分组或者存储策略时，支持检查是否有已存在的名称。

Which issue(s) this PR fixes:

Fixes #6946

Special notes for your reviewer:

Does this PR introduce a user-facing change?

在创建附件分组或者存储策略时，支持检查是否有已存在的名称。

[ruibaby]

感谢参与贡献，以下是 Review 的改进建议，请有时间看看。

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 57.23%. Comparing base (eff73dc) to head (34f10c5).
Report is 43 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #6959      +/-   ##
============================================
+ Coverage     56.99%   57.23%   +0.23%     
- Complexity     3999     4005       +6     
============================================
  Files           714      712       -2     
  Lines         24110    24123      +13     
  Branches       1585     1588       +3     
============================================
+ Hits          13742    13806      +64     
+ Misses         9756     9704      -52     
- Partials        612      613       +1     

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[ruibaby]

Hi @LEIYOUSU，感谢参与贡献，有一点非代码层面的建议：

1. PR 描述尽可能按照模板的格式，可以看看我帮你修改的。
2. 已解决的 Change Request 可以点击一下 Resolve conversation 按钮，并请求指定的人重新 Review。

[ruibaby]

我优化了一下 i18n，请看 8dda8cd，提交新的改动时，记得 pull 一下。

[LEIYOUSU]

感谢你的耐心指导和建议，我会尽快解决一下

[ruibaby]

@LEIYOUSU 不用关闭 PR 重新提交的，直接继续推送到这个分支即可。

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[ruibaby]

/lgtm

[f2c-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: guqing, ruibaby

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