fix: revise some annnotations and fix fallback check bug

[ctccxxd]

Revise some annotations and fix fallback check, originally, 1, Annotations above function is not well 2, Fallback check does not take effect

Checklist

• [ ] When introducing a new scaler, I agree with the scaling governance policy
• [x] I have verified that my change is according to the deprecations & breaking changes policy
• [ ] Tests have been added
• [x] Changelog has been updated and is aligned with our changelog requirements
• [ ] A PR is opened to update our Helm chart (repo) (if applicable, ie. when deployment manifests are modified)
• [ ] A PR is opened to update the documentation on (repo) (if applicable)
• [x] Commits are signed with Developer Certificate of Origin (DCO - learn more)

related issue https://github.com/kedacore/keda/issues/6355

[ctccxxd]

Friendly ping @zroubalik @wozniakjan @SpiritZhou @psi @wonko @fivesheep @JorTurFer hope you to review and discuss, much thanks.