Fix toggle buttons in Admin Push Rules page

What does this MR do and why?

Adds page specific style of page_bundles/settings to fix layout and functionality for expand/collapse buttons. Related to !105812 (merged)
Updates section headers to expand/collapse on click/tap. Similar to !90545 (merged)

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Navigate to Admin Area > Push Rules (http://127.0.0.1:3000/admin/push_rule)
2. Click or tap a h4 header - Push Rules and Merge request approvals
3. The section will expand / collapse

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.

Reported in Zendesk ticket(internal)