fix(app, firebase-ios-sdk): bump to firebase-ios-sdk v7.8.1 for analytics fix

Analytics fixed an issue where references to retrieveAdTrackingConsentStatus caused kids' apps to be rejected during App Store review

Author: mikehardy

packages/app/package.json

@@ -62,7 +62,7 @@
   },
   "sdkVersions": {
     "ios": {
-      "firebase": "7.8.0"
+      "firebase": "7.8.1"
     },
     "android": {
       "minSdk": 16,