adding error description to failed IAM call

Author: emawby

iOS_SDK/OneSignalSDK/Source/OSMessagingController.m

@@ -210,7 +210,7 @@ - (void)getInAppMessagesFromServer:(NSString *)subscriptionId {
         [self updateInAppMessagesFromCache];
 
     } onFailure:^(NSError *error) {
-        [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:@"getInAppMessagesFromServer failure"];
+        [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:[NSString stringWithFormat:@"getInAppMessagesFromServer failure: %@", error.localizedDescription]];
         [self updateInAppMessagesFromCache];
     }];
 }