fix: resolve the issue of receiving duplicate key error after deleting metadata

[LIlGG]

What type of PR is this?

/kind bug
/area console
/milestone 2.11.x

What this PR does / why we need it:

重构去重元数据的逻辑，解决删除元数据后仍旧提示 key 不能重复的问题。

How to test it?

1. 在文章列表点击设置按钮
2. 添加两个个空的元数据，不保存直接关闭设置框。
3. 再次打开设置框，点击删除空的元数据，查看是否会提示 key 重复。

Does this PR introduce a user-facing change?

解决删除元数据后仍旧提示 key 不能重复的问题

[codecov]

Codecov Report

Merging #4815 (3aa1328) into main (2d74312) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main    #4815   +/-   ##
=========================================
  Coverage     61.49%   61.49%           
  Complexity     2805     2805           
=========================================
  Files           405      405           
  Lines         14804    14804           
  Branches       1030     1030           
=========================================
  Hits           9103     9103           
  Misses         5205     5205           
  Partials        496      496           

[ruibaby]

/approve

[f2c-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ruibaby

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• console/OWNERS [ruibaby]

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[guqing]

/lgtm