collab_ui: Remove dependency on vcs_menu (#21016)

This PR removes the `vcs_menu` dependency from `collab_ui`.

We were only depending on this to call `vcs_menu::init`, which isn't
necessary to do here.

Release Notes:

- N/A

crates/zed/Cargo.toml

@@ -15,11 +15,11 @@ name = "zed"
 path = "src/main.rs"
 
 [dependencies]
-assistant_slash_command.workspace = true
 activity_indicator.workspace = true
 anyhow.workspace = true
 assets.workspace = true
 assistant.workspace = true
+assistant_slash_command.workspace = true
 async-watch.workspace = true
 audio.workspace = true
 auto_update.workspace = true
@@ -88,6 +88,7 @@ recent_projects.workspace = true
 release_channel.workspace = true
 remote.workspace = true
 repl.workspace = true
+reqwest_client.workspace = true
 rope.workspace = true
 search.workspace = true
 serde.workspace = true
@@ -112,11 +113,11 @@ theme_selector.workspace = true
 time.workspace = true
 toolchain_selector.workspace = true
 ui.workspace = true
-reqwest_client.workspace = true
 url.workspace = true
 urlencoding = "2.1.2"
 util.workspace = true
 uuid.workspace = true
+vcs_menu.workspace = true
 vim.workspace = true
 welcome.workspace = true
 workspace.workspace = true