Migrate branch rules settings toggle to ButtonComponent

What does this MR do and why?

This migrates the branch rules settings toggle to the ButtonComponent ViewComponent.

Screenshots or screen recordings

No visual change.

How to set up and validate locally

1. Enable the branch_rules feature flag.

   Feature.enable(:branch_rules)

2. Navigate to a project's Settings > Repository > Branch rules section.
   • The migrated button is the section's Expand/Collapse button.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #363978 (closed)