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/eval/src/eval.rs

@@ -8,6 +8,7 @@ mod tool_metrics;
 
 use assertions::{AssertionsReport, display_error_row};
 use instance::{ExampleInstance, JudgeOutput, RunOutput, run_git};
+use language_extension::LspAccess;
 pub(crate) use tool_metrics::*;
 
 use ::fs::RealFs;
@@ -415,7 +416,11 @@ pub fn init(cx: &mut App) -> Arc<AgentAppState> {
 
     language::init(cx);
     debug_adapter_extension::init(extension_host_proxy.clone(), cx);
-    language_extension::init(extension_host_proxy.clone(), languages.clone());
+    language_extension::init(
+        LspAccess::Noop,
+        extension_host_proxy.clone(),
+        languages.clone(),
+    );
     language_model::init(client.clone(), cx);
     language_models::init(user_store.clone(), client.clone(), cx);
     languages::init(languages.clone(), node_runtime.clone(), cx);