Fix clipboard buttons on "Check out branch" modal.
What does this MR do?
Fixes the clipboard button in the modal dialog opened by the "Check out branch" button on MR pages.
Are there points in the code the reviewer needs to double check?
There shouldn't be.
Why was this MR needed?
A regression in the clipboard button helper caused a style bug.
What are the relevant issue numbers?
Screenshots (if relevant)
Before:
After:
cc: @rspeicher