Finish removing git repository state and scanning logic from worktrees (#27568)

This PR completes the process of moving git repository state storage and
scanning logic from the worktree crate to `project::git_store`.

Release Notes:

- N/A

---------

Co-authored-by: Max Brunsfeld <maxbrunsfeld@gmail.com>
Co-authored-by: Conrad <conrad@zed.dev>

crates/call/src/call_impl/room.rs

@@ -469,7 +469,7 @@ impl Room {
                         let repository = repository.read(cx);
                         repositories.push(proto::RejoinRepository {
                             id: entry_id.to_proto(),
-                            scan_id: repository.completed_scan_id as u64,
+                            scan_id: repository.scan_id,
                         });
                     }