Decrease gap between MR content and sidebar

What does this MR do and why?

• Decrease gap between MR content and sidebar
• Remove ...to administrator from "Report abuse" button (it looks buggy when it wraps, plus it opens a drawer that says "Report abuse to administrator")
• Increase space below "Activity" header
• Use tertiary button for "Resolve conflicts"

Screenshots or screen recordings

Before	After

How to set up and validate locally

• Look at MR page (with :moved_mr_sidebar enabled)

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.

#394879 (closed)