Add Retry button functionality within the Apply suggestion error box

A follow-up on #324740 (closed)

Right now if you have opened merge request and failed to load metadata you'll get a wrong placeholder for the suggestion commit message, as described here: #324740 (closed)

It would be nice if a user could manually force a refresh of the metadata, to try fetching it once again and see if it completes this time. In order to do that a Retry button should be added to the Apply suggestion error message container.