Ensure that the GestureDetector is disposed

[kvpt]

I received a log from a crash of my app that is related to the SwipeAwareContainerRenderer class used by the calendar. From the stacktrace the crash seem to be caused by a press that try to access the renderer, but it has already been disposed so it crash the application. I think the solution is to force the dispose of the gesture detector to prevent that, not sure if this will be enough but it's a good start.

FYI, the stacktrace of the crash

System.NotSupportedException: Unable to activate instance of type Xamarin.Plugin.Calendar.Android.SwipeAwareContainerRenderer from native handle 0xffc46fdc (key_handle 0xe4b6c0a).
  at IJavaPeerable Java.Interop.TypeManager.CreateInstance(IntPtr handle, JniHandleOwnership transfer, Type targetType)
  at IJavaPeerable Java.Lang.Object.GetObject(IntPtr handle, JniHandleOwnership transfer, Type type)
  at IOnGestureListener Java.Lang.Object._GetObject<IOnGestureListener>(IntPtr handle, JniHandleOwnership transfer)
  at IOnGestureListener Java.Lang.Object.GetObject<IOnGestureListener>(IntPtr handle, JniHandleOwnership transfer) x 2
  at void Android.Views.GestureDetector+IOnGestureListenerInvoker.n_OnLongPress_Landroid_view_MotionEvent_(IntPtr jnienv, IntPtr native__this, IntPtr native_e)
--- End of inner exception stack trace ---
  System.MissingMethodException: No constructor found for Xamarin.Plugin.Calendar.Android.SwipeAwareContainerRenderer::.ctor(System.IntPtr, Android.Runtime.JniHandleOwnership)
    at object Java.Interop.TypeManager.CreateProxy(Type type, IntPtr handle, JniHandleOwnership transfer)
    at IJavaPeerable Java.Interop.TypeManager.CreateInstance(IntPtr handle, JniHandleOwnership transfer, Type targetType)

[kvpt]

This doesn't fix the exception, will try another way and make another PR if the alternative way fix the issue.