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>

assets/settings/default.json

@@ -783,7 +783,7 @@
   /// or to ensure Zed always downloads and installs an isolated version of node:
   /// {
   ///   "node": {
-  ///     "disable_path_lookup": true
+  ///     "ignore_system_version": true,
   ///   }
   /// NOTE: changing this setting currently requires restarting Zed.
   "node": {},