plugins: remove darwin.apple_sdk.frameworks.CoreServices from elixir plugin

The CoreServices framework reference was added to fix file_system package
compilation on macOS (PR #2462), but is no longer needed with the new Darwin
SDK pattern introduced in nixpkgs.

With the updated Darwin stdenv, the Apple SDK (including CoreServices) is
now automatically provided, making the explicit framework reference obsolete.
The old pattern using darwin.apple_sdk_11_0 has been removed from nixpkgs,
causing installation failures on macOS.

This change removes the packages section entirely and bumps the plugin
version to 0.0.2.

Fixes #2705
Fixes #2557

Author: yasuaki640

plugins/elixir.json

@@ -1,11 +1,6 @@
 {
   "name": "elixir",
-  "version": "0.0.1",
-  "packages": {
-    "darwin.apple_sdk.frameworks.CoreServices": {
-      "platforms": ["aarch64-darwin", "x86_64-darwin"]
-    }
-  },
+  "version": "0.0.2",
   "env": {
     "MIX_HOME": "{{ .Virtenv }}/mix",
     "HEX_HOME": "{{ .Virtenv }}/hex",