Fix a rare RC crash (#6556)

Author: paulb777

FirebaseRemoteConfig/CHANGELOG.md

@@ -1,5 +1,9 @@
 # v7.0.0
 - [changed] Updated `lastFetchTime` field to readonly. (#6567)
+- [changed] Functionally neutral change to stop using a deprecated AB Testing SDK method. (#6581)
+
+# v4.9.1
+- [fixed] Fix an `attempt to insert nil object` crash in `fetchWithExpirationDuration:`. (#6522)
 
 # v4.9.0
 - [fixed] Fixed `FirebaseApp.delete()` related crash in `RC Config Fetch`. (#6123)

FirebaseRemoteConfig/Sources/RCNConfigFetch.m

@@ -412,9 +412,9 @@ - (void)fetchWithUserProperties:(NSDictionary *)userProperties
         strongSelf->_settings.lastFetchError = FIRRemoteConfigErrorInternalError;
         NSDictionary<NSErrorUserInfoKey, id> *userInfo = @{
           NSLocalizedDescriptionKey :
-              (error ? [error localizedDescription]
-                     : [NSString
-                           stringWithFormat:@"Internal Error. Status code: %ld", (long)statusCode])
+              ([error localizedDescription]
+                   ?: [NSString
+                          stringWithFormat:@"Internal Error. Status code: %ld", (long)statusCode])
         };
         return [strongSelf
             reportCompletionOnHandler:completionHandler