Add closed PRs to the branch deleter

[xmo-odoo]

Currently the branch deleter is active for merged PRs, but if a PR is closed (because it's been replaced or was found unnecessary or something) then unless the closer remembers to delete the branch it's going to stay there forever clogging the branch list and the info/refs (although sadly it'll clog the info/refs of the base repository forever due to the pr magic ref).

There is no reason for that. Like with merged PRs, we should just assume that unless the branch gets reused it can be deleted.

Also the deletion delay should be reduced to 1 week, probably.