fix exception when intent is null

[rydein]

E/AndroidRuntime(21545): 	at android.app.ActivityThread.deliverResults(ActivityThread.java:4360)
E/AndroidRuntime(21545): 	at android.app.ActivityThread.handleSendResult(ActivityThread.java:4402)
E/AndroidRuntime(21545): 	at android.app.servertransaction.ActivityResultItem.execute(ActivityResultItem.java:49)
E/AndroidRuntime(21545): 	at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
E/AndroidRuntime(21545): 	at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
E/AndroidRuntime(21545): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
E/AndroidRuntime(21545): 	at android.os.Handler.dispatchMessage(Handler.java:106)
E/AndroidRuntime(21545): 	at android.os.Looper.loop(Looper.java:193)
E/AndroidRuntime(21545): 	at android.app.ActivityThread.main(ActivityThread.java:6669)
E/AndroidRuntime(21545): 	at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(21545): 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
E/AndroidRuntime(21545): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
E/AndroidRuntime(21545): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getDataString()' on a null object reference
E/AndroidRuntime(21545): 	at com.flutter_webview_plugin.WebviewManager$ResultHandler.handleResult(WebviewManager.java:46)
E/AndroidRuntime(21545): 	at com.flutter_webview_plugin.FlutterWebviewPlugin.onActivityResult(FlutterWebviewPlugin.java:241)
E/AndroidRuntime(21545): 	at io.flutter.app.FlutterPluginRegistry.onActivityResult(FlutterPluginRegistry.java:210)
E/AndroidRuntime(21545): 	at io.flutter.app.FlutterActivityDelegate.onActivityResult(FlutterActivityDelegate.java:139)
E/AndroidRuntime(21545): 	at io.flutter.app.FlutterActivity.onActivityResult(FlutterActivity.java:138)
E/AndroidRuntime(21545): 	at com.example.MainActivity.onActivityResult(MainActivity.kt:77)
E/AndroidRuntime(21545): 	at android.app.Activity.dispatchActivityResult(Activity.java:7454)
E/AndroidRuntime(21545): 	at android.app.ActivityThread.deliverResults(ActivityThread.java:4353)
E/AndroidRuntime(21545): 	... 11 more

[charafau]

Thanks for contribution!