feat(ios): Turn on debug by default

Author: MaximBelov

src/ios/AppDelegate+FirebasePlugin.m

@@ -49,6 +49,11 @@ - (NSNumber *)applicationInBackground {
 - (BOOL)application:(UIApplication *)application swizzledDidFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     [self application:application swizzledDidFinishLaunchingWithOptions:launchOptions];
 
+    #if DEBUG
+        [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"/google/firebase/debug_mode"];
+        [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"/google/measurement/debug_mode"];
+    #endif
+    
     @try{
         instance = self;