[sdk] Add 7 metadataStore methods to Client

[t-kikuc]

What this PR does:

as title

Why we need it:

To make it easier for plugin developers to call methods of metadataStore.

Which issue(s) this PR fixes:

Part of #5530

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 53 lines in your changes missing coverage. Please review.

Project coverage is 26.29%. Comparing base (936879c) to head (522eb4e).
Report is 13 commits behind head on master.

Files with missing lines	Patch %	Lines
pkg/plugin/pipedsdk/client.go	0.00%	53 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5565      +/-   ##
==========================================
- Coverage   26.31%   26.29%   -0.02%     
==========================================
  Files         467      468       +1     
  Lines       50099    50152      +53     
==========================================
+ Hits        13185    13189       +4     
- Misses      35858    35908      +50     
+ Partials     1056     1055       -1     

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[Warashi]

Thank you! LGTM!

[khanhtc1202]

👍