feat: add click-away and mounting logic to agent setting component

[fdb02983rhy]

Summary

Closes https://github.com/langgenius/dify/issues/15523

[!Tip] Close issue syntax: Fixes #<issue number> or Resolves #<issue number>, see documentation for more details.

Screenshots

Before

https://github.com/user-attachments/assets/e924d135-e140-40dd-bce5-1975d47542be

After

https://github.com/user-attachments/assets/39610b87-794c-4d54-9d64-88052b966e0e

Checklist

[!IMPORTANT]
Please review the checklist below before submitting your pull request.

• [ ] This change requires a documentation update, included: Dify Document
• [x] I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• [x] I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• [x] I've updated the documentation accordingly.
• [x] I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods