Replace link to Resolve conflicts with buttons

What does this MR do?

• Fix subtle links to "Resolve these conflicts" with buttons to make then less subtle
• Rewords merge conflicts message in the MR widget box
• Replace the word "manually" with "locally"

Why was this MR needed?

• The links to resolve these conflicts and "merge manually" where too subtle
• Needed to improve UX to let the user know these are actionable items

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #21135 (closed)