Resolve "Add Copy to Clipboard Button to Review App Modal"

What does this MR do?

What it says on the tin: Adds the button from gitlab-ce!28676 to the Visual Review instruction modal. Also slightly adjusts the button.

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines
• Style guides
• Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Closes #11707 (closed)