Fixes Issue with VideoPlayerController.file

[JonasJW]

Description

This PR adds the lines

 'formatHint': _videoFormatStringMap[dataSource.formatHint],
'useCache': dataSource.useCache

To the create method of method_channel_video_player.dart

Without it I get this error:

E/flutter (27050): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: PlatformException(error, Attempt to invoke virtual method 'boolean java.lang.Boolean.booleanValue()' on a null object reference, null)
E/flutter (27050): #0 StandardMethodCodec.decodeEnvelope package:flutter/…/services/message_codecs.dart:569
E/flutter (27050): #1 MethodChannel._invokeMethod package:flutter/…/services/platform_channel.dart:156
E/flutter (27050): <asynchronous suspension>
E/flutter (27050): #2 MethodChannel.invokeMethod E/flutter (27050): #3 MethodChannel.invokeMapMethod package:flutter/…/services/platform_channel.dart:356
E/flutter (27050): #4 MethodChannelVideoPlayer.create package:video_player_platform_interface/method_channel_video_player.dart:57
E/flutter (27050): #5 VideoPlayerController.initialize package:video_player/video_player.dart:303
E/flutter (27050): <asynchronous suspension>
E/flutter (27050): #6 _DownloadTestPageState.load package:flutter_video_test/…/video-test/download-test.dart:30
E/flutter (27050): #7 _rootRunUnary (dart:async/zone.dart:1192:38)
E/flutter (27050): #8 _CustomZone.runUnary (dart:async/zone.dart:1085:19)
E/flutter (27050): #9 _FutureListener.handleValue (dart:async/future_impl.dart:141:18)
E/flutter (27050): #10 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:682:45)
E/flutter (27050): #11 Future._propagateToListeners (dart:async/future_impl.dart:711:32)
E/flutter (27050): #12 Future._completeWithValue (dart:async/future_impl.dart:526:5)
E/flutter (27050): #13 _AsyncAwaitCompleter.complete (dart:async-patch/async_patch.dart:36:15)
E/flutter (27050): #14 _completeOnAsyncReturn (dart:async-patch/async_patch.dart:298:13)
E/flutter (27050): #15 BaseCacheManager.getSingleFile (package:flutter_cache_manager/src/cache_manager.dart)
E/flutter (27050): #16 _rootRunUnary (dart:async/zone.dart:1192:38)
E/flutter (27050): #17 _CustomZone.runUnary (dart:async/zone.dart:1085:19)
E/flutter (27050): #18 _FutureListener.handleValue (dart:async/future_impl.dart:141:18)
E/flutter (27050): #19 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:682:45)
E/flutter (27050): #20 Future._propagateToListeners (dart:async/future_impl.dart:711:32)
E/flutter (27050): #21 Future._completeWithValue (dart:async/future_impl.dart:526:5)
E/flutter (27050): #22 _AsyncAwaitCompleter.complete (dart:async-patch/async_patch.dart:36:15)
E/flutter (27050): #23 _completeOnAsyncReturn (dart:async-patch/async_patch.dart:298:13)
E/flutter (27050): #24 CacheStore.getFile (package:flutter_cache_manager/src/cache_store.dart)
E/flutter (27050): #25 _rootRunUnary (dart:async/zone.dart:1192:38)
E/flutter (27050): #26 _CustomZone.runUnary (dart:async/zone.dart:1085:19)
E/flutter (27050): #27 _FutureListener.handleValue (dart:async/future_impl.dart:141:18)
E/flutter (27050): #28 Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:682:45)
E/flutter (27050): #29 Future._propagateToListeners (dart:async/future_impl.dart:711:32)
E/flutter (27050): #30 Future._addListener.<anonymous closure> (dart:async/future_impl.dart:391:9)
E/flutter (27050): #31 _rootRun (dart:async/zone.dart:1184:13)
E/flutter (27050): #32 _CustomZone.run (dart:async/zone.dart:1077:19)
E/flutter (27050): #33 _CustomZone.runGuarded (dart:async/zone.dart:979:7)
E/flutter (27050): #34 _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1019:23)
E/flutter (27050): #35 _microtaskLoop (dart:async/schedule_microtask.dart:43:21)
E/flutter (27050): #36 _startMicrotaskLoop (dart:async/schedule_microtask.dart:52:5)