fix(ios, sdk): bump to firebase-ios-sdk 8.12.1

fixes a few issues, mostly related to iOS15 "pre-warming"
check upstream release notes to see if you are affected

Author: mikehardy

packages/app/package.json

@@ -65,7 +65,7 @@
   },
   "sdkVersions": {
     "ios": {
-      "firebase": "8.11.0"
+      "firebase": "8.12.1"
     },
     "android": {
       "minSdk": 19,