remove -exp deps from firestore (#3261)

Author: Feiyang1

packages/firestore/package.json

@@ -67,8 +67,6 @@
     "@firebase/app-types": "0.x"
   },
   "devDependencies": {
-    "@firebase/app-exp": "0.x",
-    "@firebase/app-types-exp": "0.x",
     "@rollup/plugin-alias": "3.1.1",
     "@types/json-stable-stringify": "1.0.32",
     "json-stable-stringify": "1.0.1",