Handle when merge strategy is already set by the merge queue

I believe there is an argument we're setting on the merge that should not be used. it happens whether i use squash or merge. this particular repository uses squash.

Start by tracing the merge action and its handling of GitHub merge-queue settings; compare behavior for squash and merge using the issue's reported scenarios. Reproduce the argument error, then verify that the merge request no longer conflicts with the strategy selected by the queue.

Written by the indexing model from the issue text.