chore: remove mjs target

@actions/http-client is not bundled correctly

Author: aminya

dist/actions_python.318ba25a.js

@@ -10,7 +10,6 @@
     "require": "./dist/setup-cpp.js"
   },
   "main": "./dist/setup_cpp.js",
-  "module": "./dist/setup_cpp.mjs",
   "source": "./src/main.ts",
   "bin": {
     "setup-cpp": "./dist/setup_cpp.js",
@@ -148,12 +147,6 @@
       "includeNodeModules": true,
       "optimize": true,
       "outputFormat": "commonjs"
-    },
-    "module": {
-      "context": "node",
-      "includeNodeModules": true,
-      "optimize": true,
-      "outputFormat": "esmodule"
     }
   }
 }