Fix issues with extension API that come up when moving Svelte into an extension (#9611)

We're doing it. Svelte support is moving into an extension. This PR
fixes some issues that came up along the way.

Notes

* extensions need to be able to retrieve the path the `node` binary
installed by Zed
* previously we were silently swallowing any errors that occurred while
loading a grammar
* npm commands ran by extensions weren't run in the right directory
* Tree-sitter's WASM stdlib didn't support a C function (`strncmp`)
needed by the Svelte parser's external scanner
* the way that LSP installation status was reported was unnecessarily
complex

Release Notes:

- Removed built-in support for the Svelte and Gleam languages, because
full support for those languages is now available via extensions. These
extensions will be suggested for download when you open a `.svelte` or
`.gleam` file.

---------

Co-authored-by: Marshall <marshall@zed.dev>

crates/collab/src/rpc.rs

@@ -1228,25 +1228,21 @@ async fn create_room(
 ) -> Result<()> {
     let live_kit_room = nanoid::nanoid!(30);
 
-    let live_kit_connection_info = {
-        let live_kit_room = live_kit_room.clone();
+    let live_kit_connection_info = util::maybe!(async {
         let live_kit = session.live_kit_client.as_ref();
+        let live_kit = live_kit?;
         let user_id = session.user_id().to_string();
 
-        util::async_maybe!({
-            let live_kit = live_kit?;
+        let token = live_kit
+            .room_token(&live_kit_room, &user_id.to_string())
+            .trace_err()?;
 
-            let token = live_kit
-                .room_token(&live_kit_room, &user_id.to_string())
-                .trace_err()?;
-
-            Some(proto::LiveKitConnectionInfo {
-                server_url: live_kit.url().into(),
-                token,
-                can_publish: true,
-            })
+        Some(proto::LiveKitConnectionInfo {
+            server_url: live_kit.url().into(),
+            token,
+            can_publish: true,
         })
-    }
+    })
     .await;
 
     let room = session