Add branch to git panel (#24485)

This PR adds the branch selector to the git panel and fixes a few bugs
in the repository selector.

Release Notes:

- N/A

---------

Co-authored-by: ConradIrwin <conrad.irwin@gmail.com>
Co-authored-by: Conrad <conrad@zed.dev>

crates/zed/src/main.rs

@@ -505,7 +505,6 @@ fn main() {
         notifications::init(app_state.client.clone(), app_state.user_store.clone(), cx);
         collab_ui::init(&app_state, cx);
         git_ui::init(cx);
-        vcs_menu::init(cx);
         feedback::init(cx);
         markdown_preview::init(cx);
         welcome::init(cx);