Stop extensions' servers and message loops before removing their files (#34208)

Fixes an issue that caused Windows to fail when removing extension's
directories, as Zed had never stop any related processes.

Now:

* Zed shuts down and waits until the end when the language servers are
shut down

* Adds `impl Drop for WasmExtension` where does
`self.tx.close_channel();` to stop a receiver loop that holds the "lock"
on the extension's work dir.
The extension was dropped, but the channel was not closed for some
reason.

* Does more unregistration to ensure `Arc<WasmExtension>` with the `tx`
does not leak further

* Tidies up the related errors which had never reported a problematic
path before

Release Notes:

- N/A

---------

Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>
Co-authored-by: Smit <smit@zed.dev>

crates/project/src/project.rs

@@ -3217,9 +3217,11 @@ impl Project {
         also_restart_servers: HashSet<LanguageServerSelector>,
         cx: &mut Context<Self>,
     ) {
-        self.lsp_store.update(cx, |lsp_store, cx| {
-            lsp_store.stop_language_servers_for_buffers(buffers, also_restart_servers, cx)
-        })
+        self.lsp_store
+            .update(cx, |lsp_store, cx| {
+                lsp_store.stop_language_servers_for_buffers(buffers, also_restart_servers, cx)
+            })
+            .detach_and_log_err(cx);
     }
 
     pub fn cancel_language_server_work_for_buffers(