[BUG] - Crash occurs when trying to long press (scroll) on a non-text node on Android/iOS.

[rafalplonka]

Package Version
super_editor, GitHub, stable branch

User Info
Knips (https://knips.io) - We are working on replacing our Block Text Editor with the Super Editor (not released yet). The editor will be used to create posts on our platform.

To Reproduce

1. Build the demo app on Android/iOS.
2. Add a non-text node, such as an image or divider.
3. Long press on the node (this could happen when a user is trying to scroll).
4. The app crashes.

Minimal Reproduction Code
The bug is present in the demo app.

Actual behavior
Crash

The following _TypeError was thrown while handling a gesture:
Null check operator used on a null value

When the exception was thrown, this was the stack: 
#0      AndroidDocumentLongPressSelectionStrategy.onLongPressDragUpdate (package:super_editor/src/infrastructure/platforms/android/long_press_selection.dart:221:74)
#1      _AndroidDocumentTouchInteractorState._onLongPressPanUpdate (package:super_editor/src/default_editor/document_gestures_touch_android.dart:1072:25)
#2      _AndroidDocumentTouchInteractorState._onPanUpdate (package:super_editor/src/default_editor/document_gestures_touch_android.dart:1050:7)
#3      DragGestureRecognizer._checkUpdate.<anonymous closure> (package:flutter/src/gestures/monodrag.dart:806:55)
#4      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:344:24)
#5      DragGestureRecognizer._checkUpdate (package:flutter/src/gestures/monodrag.dart:806:7)
#6      DragGestureRecognizer.handleEvent (package:flutter/src/gestures/monodrag.dart:652:11)
#7      PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:98:12)
#8      PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:143:9)
#9      _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:633:13)
#10     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:141:18)
#11     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:127:7)
#12     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:495:19)
#13     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:475:22)
#14     RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:425:11)
#15     GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:420:7)
#16     GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:383:5)
#17     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:330:7)
#18     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:299:9)
#19     _invoke1 (dart:ui/hooks.dart:328:13)
#20     PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:442:7)
#21     _dispatchPointerDataPacket (dart:ui/hooks.dart:262:31)
Handler: "onUpdate"
Recognizer: VerticalDragGestureRecognizer#7209a
  start behavior: down

Expected behavior
No crash, user is able to scroll/long-press without any issue

Platform
Android/iOS

Flutter version
3.22.2