[migration-tools] Pull all branches prior to changing remote

[cottsay]

There are two reasons this is probably the right thing to do:

1. When the remote gets modified, it breaks Blooms mechanism for determining when a branch already exists remotely prior to creating a new one, which has previously resulted in obliterating the release and patch branches during same-distro migrations.
2. When the repository is moved from one location to another, we end up mirroring all the tags from the original location but only mirroring the branches from the source and destination distros, which is weird. This way we'll mirror everything.

Marking as draft until I can test that this doesn't regress migration to a different distro.

Fixes #32128

[nuclearsandwich]

Another possibility here is to implement the full mirror clone and push that I have been doing for pre-emptive ros2-gbp repo creation. I think the net effect would be the same but it might be easier to audit.

Because of the way git's data model and work trees interact we cannot use --mirror or an equivalent refspec with git-fetch origin +refs/*:refs/* with a clone containing a worktree. So we'd either need to create a mirror clone initially and then manually create a worktree (which bloom's git handling may not be able to deal with) or manually fetch, checkout, and push all refs. Which the track_branches from bloom may be doing for us.

[nuclearsandwich]

@cottsay should we use the last of our shift on Monday to either polish this off and merge it or close it out?

[github-actions]

This PR hasn't been activity in 14 days. If you are still are interested in getting it merged please provide an update. Otherwise it will likely be closed by a rosdistro maintainer following our contributing policy. It's been labeled "stale" for visibility to the maintainers. If this label isn't appropriate, you can ask a maintainer to remove the label and add the 'persistent' label.

[github-actions]

This PR hasn't been activity in 14 days. If you are still are interested in getting it merged please provide an update. Otherwise it will likely be closed by a rosdistro maintainer following our contributing policy. It's been labeled "stale" for visibility to the maintainers. If this label isn't appropriate, you can ask a maintainer to remove the label and add the 'persistent' label.

[mjcarroll]

@cottsay and @nuclearsandwich any updates on this one?

[mjcarroll]

@cottsay and @nuclearsandwich any updates on this one?