On pull requests, the merge UI should not timeout before the server request

Issue Summary

When merging a pull request, if that merge takes longer than the default timeout in the UI (1 minute) then the UI will indeed timeout the request before the server request finishes the merge. We allow up to 5 minutes for a merge to finish, so the UI should wait for the server request to finish.

Steps to Reproduce

1. Attempt to merge a pull request that is sufficiently large that the merge will take longer than 60 seconds

Expected Results

The UI will wait until the server request finishes.

Actual Results

The UI times out (Note that the merge will still continue in the background)

Workaround

No workaround necessary.