added an onCaptionsDeviceSettings event

ios/Video/RCTVideo.m

@@ -68,6 +68,7 @@ static int const RCTVideoUnset = -1;
 #if __has_include(<react-native-video/RCTVideoCache.h>)
   RCTVideoCache * _videoCache;
 #endif
+  BOOL _deviceCaptionsEnabled;
 }
 
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher
@@ -364,6 +365,12 @@ static int const RCTVideoUnset = -1;
                                     @"target": self.reactTag
                                 });
       }
+
+      if (self.onCaptionsDeviceSetting) {
+        self.onCaptionsDeviceSetting(@{@"deviceCaptionsEnabled": [NSNumber numberWithBool:_deviceCaptionsEnabled],
+                                     @"target": self.reactTag
+                                     });
+      }
     }];
   });
   _videoLoadStarted = YES;
@@ -966,9 +973,7 @@ static int const RCTVideoUnset = -1;
   
   // in the situation that a selected text track is not available (eg. specifies a textTrack not available)
   if (![type isEqualToString:@"disabled"] && selectedTrackIndex == RCTVideoUnset) {
-    CFArrayRef captioningMediaCharacteristics = MACaptionAppearanceCopyPreferredCaptioningMediaCharacteristics(kMACaptionAppearanceDomainUser);
-    NSArray *captionSettings = (__bridge NSArray*)captioningMediaCharacteristics;
-    if ([captionSettings containsObject:AVMediaCharacteristicTranscribesSpokenDialogForAccessibility]) {
+    if (_deviceCaptionsEnabled) {
       selectedTrackIndex = 0; // If we can't find a match, use the first available track
       NSString *systemLanguage = [[NSLocale preferredLanguages] firstObject];
       for (int i = 0; i < textTracks.count; ++i) {