fix: prevent agent model picker button side effects

[WangShen007]

Summary

• Set the agent model configuration button to an explicit non-submit button type.
• Stop/prevent the click event from bubbling to the surrounding selectable row, so opening model config no longer triggers the unwanted navigation/return behavior.

Upstream status note

• After the maintainer's latest update, the author may have already fixed the issue; user re-testing on Windows 11 indicates the current upstream behavior appears to be working correctly. This PR can be treated as a supplemental minimal fix/reference if still needed.

Linked issue

Closes #1

Test plan

• Windows 11 real-machine test.
• Ran pnpm dev from C:\notebook\Reviva.
• Verified Vite served successfully and the Electron window launched as Reviva.
• Verified clicking the assistant model configuration button no longer triggers the previous row navigation/return behavior.