Due to the refactor of BranchConfig, the tests for `pr create` no longer
require a handful of stubbed git commands.
Additionally, I noticed some overlap between `pr create`'s existing logic
with the new finder code. I suspect that the finder's new ParsePRRefs
helper could be leveraged here as well, which would allow us to respect
non-centralized workflows pr create in the same way we are respecting them
in `gh pr view` and `gh pr status`
4382bdf072