Fix "Edit" button on blame page without repo permissions

What does this MR do?

Without repo permissions, on a blame page, clicking "Edit" will bring up the Fork/Cancel button just like it does on the blob:show page.

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Without repo permissions, on a blame page, clicking "Edit" would do nothing.

Does this MR meet the acceptance criteria?

• 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 #30636 (closed)