fix: different concreate types still cause panic

[kevwan]

fix #4594

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.54%. Comparing base (8690859) to head (c52af3a).
Report is 232 commits behind head on master.

Additional details and impacted files

Files with missing lines	Coverage Δ
rest/httpx/requests.go	100.00% <100.00%> (ø)

... and 7 files with indirect coverage changes

[kevwan]

Review Summary:

• Thread Safety Improvement: The changes replace sync/atomic with sync and use sync.RWMutex to ensure thread-safe access and modification of the validator.
• Test Case Addition: A new test case TestSetValidatorTwice has been added to verify that setting the validator multiple times does not lead to a panic, addressing the issue of storing inconsistently typed values into atomic.Value.