Make GitRepository::status async and remove cx parameter (#27514)

This lays the groundwork for using `status` as part of the new agent
panel.

Release Notes:

- N/A

crates/extension_cli/Cargo.toml

@@ -18,6 +18,7 @@ clap = { workspace = true, features = ["derive"] }
 env_logger.workspace = true
 extension.workspace = true
 fs.workspace = true
+gpui.workspace = true
 language.workspace = true
 log.workspace = true
 reqwest_client.workspace = true