fix(ios): determine captured audio type from file instead of hardcode…

…d value

Previously forced "audio/wav" but not always correct: from file can be "audio/x-wav" or other.

src/ios/CDVCapture.m

@@ -914,7 +914,7 @@ - (void)audioRecorderDidFinishRecording:(AVAudioRecorder*)recorder successfully:
     if (flag) {
         NSString* filePath = [avRecorder.url path];
         // NSLog(@"filePath: %@", filePath);
-        NSDictionary* fileDict = [captureCommand getMediaDictionaryFromPath:filePath ofType:@"audio/wav"];
+        NSDictionary* fileDict = [captureCommand getMediaDictionaryFromPath:filePath ofType:nil];
         NSArray* fileArray = [NSArray arrayWithObject:fileDict];
 
         self.pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK messageAsArray:fileArray];