[RN] Fix input dialog value bug

react/features/base/dialog/components/native/BaseDialog.js

 
     _onCancel: () => void;
 
-    _onSubmit: () => boolean;
+    _onSubmit: ?string => boolean;
 
     /**
      * Renders the content of the dialog.

react/features/base/dialog/components/native/InputDialog.js

                 <View style = { brandedDialog.buttonWrapper }>
                     <TouchableOpacity
                         disabled = { okDisabled }
-                        onPress = { this._onSubmit }
+                        onPress = { this._onSubmitValue }
                         style = { [
                             brandedDialog.button,
                             brandedDialog.buttonFarLeft,
         });
     }
 
-    _onSubmit: ?string => boolean;
+    _onSubmit: (?string) => boolean;
 
     _onSubmitValue: () => boolean;