[UT] refactor ut of paimon metadata

[miomiocat]

Fixes #issue

What type of PR is this:

• BugFix
• Feature
• Enhancement
• Refactor
• UT
• Doc
• Tool

Does this PR entail a change in behavior?

• Yes, this PR will result in a change in behavior.
• No, this PR will not result in a change in behavior.

If yes, please specify the type of change:

• Interface/UI changes: syntax, type conversion, expression evaluation, display information
• Parameter changes: default values, similar parameters but with different default values
• Policy changes: use new policy to replace old one, functionality automatically enabled
• Feature removed
• Miscellaneous: upgrade & downgrade compatibility, etc.

Checklist:

• I have added test cases for my bug fix or my new feature
• This pr needs user documentation (for new or modified features or behaviors)
  • I have added documentation for my new feature or new function

Bugfix cherry-pick branch check:

• I have checked the version labels which the pr will be auto-backported to the target branch
  • 3.1
  • 3.0
  • 2.5
  • 2.4

[sonarqubecloud]

SonarCloud Quality Gate failed.   

4 Bugs
0 Vulnerabilities
0 Security Hotspots
73 Code Smells

0.0% Coverage
2.7% Duplication

Catch issues before they fail your Quality Gate with our IDE extension SonarLint

[wanpengfei-git]

[BE Incremental Coverage Report]

😍 pass : 0 / 0 (0%)

[wanpengfei-git]

[FE Incremental Coverage Report]

😍 pass : 0 / 0 (0%)