Omit tsdk_path from the servers' options if it does not exist (#23525)

Part of https://github.com/zed-industries/zed/issues/22606

Before, `tsdk_path` for vtsls and typescript-language-server
unconditionally set a `tsdk`/`tsserver` property for the corresponding
language server, even if there were no such directory at all.
Instead, make the corresponding code to omit such property if it was not
found on the FS.

Release Notes:

- Fixed "The path /.../tsserver.js doesn't point to a valid tsserver
install. Falling back to bundled TypeScript version." pop-up appearing

crates/languages/src/css.rs

@@ -4,6 +4,7 @@ use futures::StreamExt;
 use language::{LspAdapter, LspAdapterDelegate};
 use lsp::{LanguageServerBinary, LanguageServerName};
 use node_runtime::NodeRuntime;
+use project::Fs;
 use serde_json::json;
 use smol::fs;
 use std::{
@@ -107,6 +108,7 @@ impl LspAdapter for CssLspAdapter {
 
     async fn initialization_options(
         self: Arc<Self>,
+        _: &dyn Fs,
         _: &Arc<dyn LspAdapterDelegate>,
     ) -> Result<Option<serde_json::Value>> {
         Ok(Some(json!({