Added unit tests for safe lua lifted libraries

[anujagrawal699]

Description:
This PR introduces comprehensive unit tests for the safe Lua library utility functions in the pkg/util/lifted/lua package. These additions aim to increase code reliability, maintainability, and test coverage for the Lua libraries lifted from argo-cd and gopher-lua.

Additions & Modifications:

1. pkg/util/lifted/lua/loadlib_safe_test.go
2. pkg/util/lifted/lua/oslib_safe_test.go

Test Coverage:

1. pkg/util/lifted/lua/loadlib_safe_test.go : 0% to 95.80%
2. pkg/util/lifted/lua/oslib_safe_test.go : 52.14% to 94.50%

What type of PR is this?
/kind feature

Which issue(s) this PR fixes:
Fixes a part of #5470

Does this PR introduce a user-facing change?:

NONE

[karmada-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.28%. Comparing base (e08cea1) to head (efff5bc).

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5819      +/-   ##
==========================================
+ Coverage   43.16%   43.28%   +0.12%     
==========================================
  Files         658      658              
  Lines       56006    56006              
==========================================
+ Hits        24173    24244      +71     
+ Misses      30263    30191      -72     
- Partials     1570     1571       +1     

Flag	Coverage Δ
unittests	43.28% <ø> (+0.12%)	⬆️

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[XiShanYongYe-Chang]

/cc @zhzhuang-zju

[XiShanYongYe-Chang]

/assign

[zhzhuang-zju]

Nice improvement!