lsp: Remove reinstall, update config (#18318)

Release Notes:

- Fixed overriding the path of a language server binary for all language
servers. `{"lsp":{"<lsp-name>":{"binary":{"path": "_"}}}}` will now work
for all language servers including those defined by extensions.
- (breaking change) To disable finding lsp adapters in your path, you
must now specify
`{"lsp":{"<lsp-name>":{"binary":{"ignore_system_version": true}}}}`.
Previously this was `{"lsp":{"<lsp-name>":{"binary":{"path_lookup":
false}}}}`. Note that this setting still does not apply to extensions.
- Removed automatic reinstallation of language servers. (It mostly
didn't work)

---------

Co-authored-by: Mikayla <mikayla@zed.dev>

crates/languages/src/python.rs

@@ -97,13 +97,6 @@ impl LspAdapter for PythonLspAdapter {
         get_cached_server_binary(container_dir, &self.node).await
     }
 
-    async fn installation_test_binary(
-        &self,
-        container_dir: PathBuf,
-    ) -> Option<LanguageServerBinary> {
-        get_cached_server_binary(container_dir, &self.node).await
-    }
-
     async fn process_completions(&self, items: &mut [lsp::CompletionItem]) {
         // Pyright assigns each completion item a `sortText` of the form `XX.YYYY.name`.
         // Where `XX` is the sorting category, `YYYY` is based on most recent usage,