Fix git installation bugs and UX

[chennes]

Using git to install large addons now doesn't try to use the progress bar (it wasn't a good idea, git's progress is chunked and non-linear). Also address a non-responsiveness problem on Windows, and a dialog-resizing issue.

[github-actions]

Backport failed for main, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin main
git worktree add -d .worktree/backport-485-to-main origin/main
cd .worktree/backport-485-to-main
git switch --create backport-485-to-main
git cherry-pick -x 051d86ec938cc7c354fd4759ff8013f6891229d2

[github-actions]

Backport failed for main, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin main
git worktree add -d .worktree/backport-485-to-main origin/main
cd .worktree/backport-485-to-main
git switch --create backport-485-to-main
git cherry-pick -x 051d86ec938cc7c354fd4759ff8013f6891229d2