Fix crash on onAudioRouteChange when output is nil

Author: manuquentin

ios/RNCallKeep/RNCallKeep.m

@@ -126,7 +126,11 @@ - (void)onAudioRouteChange:(NSNotification *)notification
 {
     NSDictionary *info = notification.userInfo;
     NSInteger reason = [[info valueForKey:AVAudioSessionRouteChangeReasonKey] integerValue];
-    NSString *output = [AVAudioSession sharedInstance].currentRoute.outputs.count > 0 ? [AVAudioSession sharedInstance].currentRoute.outputs[0].portType : nil;
+    NSString *output = [RNCallKeep getAudioOutput];
+
+    if (output == nil) {
+        return;
+    }
 
     [self sendEventWithName:RNCallKeepDidChangeAudioRoute body:@{
         @"output": output,
@@ -154,6 +158,10 @@ + (void)initCallKitProvider {
     }
 }
 
++ (NSString *) getAudioOutput {
+    return [AVAudioSession sharedInstance].currentRoute.outputs.count > 0 ? [AVAudioSession sharedInstance].currentRoute.outputs[0].portType : nil;
+}
+
 + (void)setup:(NSDictionary *)options {
     RNCallKeep *callKeep = [RNCallKeep allocWithZone: nil];
     [callKeep setup:options];
@@ -203,7 +211,7 @@ + (void)setup:(NSDictionary *)options {
 #ifdef DEBUG
     NSLog(@"[RNCallKeep][checkSpeaker]");
 #endif
-    NSString *output = [AVAudioSession sharedInstance].currentRoute.outputs.count > 0 ? [AVAudioSession sharedInstance].currentRoute.outputs[0].portType : nil;
+    NSString *output = [RNCallKeep getAudioOutput];
     resolve(@([output isEqualToString:@"Speaker"]));
 }