Restore state when closing - reopening Wiredash

[passsy]

There has been reports of crashes - see below - that where caused by the feedback flow not reflecting the actual state when reopening wiredash. This is now fixed. Added a test for it

When the exception was thrown, this was the stack: 
#0      FeedbackModel.goToNextStep (package:wiredash/src/feedback/feedback_model.dart:197:7)
#1      _TronButtonState._handleTapUp (package:wiredash/src/core/widgets/tron/tron_button.dart:212:19)
#2      TapGestureRecognizer.handleTapUp.<anonymous closure> (package:flutter/src/gestures/tap.dart:611:57)
#3      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:198:24)
#4      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:611:11)
#5      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:298:5)
#6      BaseTapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:269:7)
#7      GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:157:27)
#8      GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:443:20)
#9      GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:419:22)
#10     RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:322:11)
#11     GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:374:7)
#12     GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:338:5)
#13     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:296:7)
#14     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:279:7)
#18     _invoke1 (dart:ui/hooks.dart:170:10)
#19     PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:331:7)
#20     _dispatchPointerDataPacket (dart:ui/hooks.dart:94:31)