test(affix): improve test coverage of affix (#5981)

* test(affix): refactored the test file of the Affix component

- Refactored the test file of the Affix component

* test(unit): optimization

* test(unit): optimization

* chore: stash changelog [ci skip]

---------

Co-authored-by: zhangpaopao <zhangpaopao0609@gmail.com>
Co-authored-by: tdesign-bot <tdesign@tencent.com>

Author: 3 people