Crash: IndexOutOfBoundsException When Inserting Checklist Item Above Empty Checklist Item

### Expected
When tapping the **_Enter_**/**_Return_** key at the end of a line of a checklist item with the next line containing an empty checklist item and the line after that being a checklist item, the app inserts a new checklist item and does not crash.

### Observed
When tapping the **_Enter_**/**_Return_** key at the end of a line of a checklist item with the next line containing an empty checklist item and the line after that being a checklist item, the app does not insert a new checklist item and does crash. See the stack trace below for details.

Stack Trace

java.lang.IndexOutOfBoundsException: 5, -1

    at android.text.PackedIntVector.deleteAt(PackedIntVector.java:222)

    at android.text.DynamicLayout.reflow(DynamicLayout.java:317)

    at android.text.DynamicLayout.-wrap0

    at android.text.DynamicLayout$ChangeWatcher.reflow(DynamicLayout.java:750)

    at android.text.DynamicLayout$ChangeWatcher.onSpanChanged(DynamicLayout.java:779)

    at android.text.SpannableStringBuilder.sendSpanChanged(SpannableStringBuilder.java:1292)

    at android.text.SpannableStringBuilder.sendToSpanWatchers(SpannableStringBuilder.java:647)

    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:577)

    at android.text.SpannableStringBuilder.insert(SpannableStringBuilder.java:224)

    at android.text.SpannableStringBuilder.insert(SpannableStringBuilder.java:222)

    at com.automattic.simplenote.utils.AutoBullet.apply

    at com.automattic.simplenote.NoteEditorFragment.attemptAutoList

    at com.automattic.simplenote.NoteEditorFragment.afterTextChanged

    at android.widget.TextView.sendAfterTextChanged(TextView.java:9375)

    at android.widget.TextView$ChangeWatcher.afterTextChanged(TextView.java:11917)

    at android.text.SpannableStringBuilder.sendAfterTextChanged(SpannableStringBuilder.java:1262)

    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:574)

    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:504)

    at android.text.SpannableStringBuilder.replace(SpannableStringBuilder.java:502)

    at android.text.method.QwertyKeyListener.onKeyDown(QwertyKeyListener.java:228)

    at android.text.method.TextKeyListener.onKeyDown(TextKeyListener.java:141)

    at android.widget.TextView.doKeyDown(TextView.java:7316)

    at android.widget.TextView.onKeyDown(TextView.java:7093)

    at android.view.KeyEvent.dispatch(KeyEvent.java:2688)

    at android.view.View.dispatchKeyEvent(View.java:11662)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at androidx.core.widget.NestedScrollView.dispatchKeyEvent

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at androidx.core.widget.NestedScrollView.dispatchKeyEvent

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at androidx.viewpager.widget.ViewPager.dispatchKeyEvent

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1827)

    at com.android.internal.policy.DecorView.superDispatchKeyEvent(DecorView.java:437)

    at com.android.internal.policy.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1818)

    at androidx.core.view.KeyEventDispatcher.activitySuperDispatchKeyEventPre28

    at androidx.core.view.KeyEventDispatcher.dispatchKeyEvent

    at androidx.core.app.ComponentActivity.dispatchKeyEvent

    at androidx.appcompat.app.AppCompatActivity.dispatchKeyEvent

    at androidx.appcompat.view.WindowCallbackWrapper.dispatchKeyEvent

    at androidx.appcompat.app.AppCompatDelegateImpl$AppCompatWindowCallback.dispatchKeyEvent

    at androidx.appcompat.view.WindowCallbackWrapper.dispatchKeyEvent

    at com.android.internal.policy.DecorView.dispatchKeyEvent(DecorView.java:351)

    at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:4714)

    at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4586)

    at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4128)

    at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4181)

    at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4147)

    at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4274)

    at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4155)

    at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4331)

    at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4128)

    at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4181)

    at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4147)

    at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4155)

    at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4128)

    at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4181)

    at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4147)

    at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4307)

    at android.view.ViewRootImpl$ImeInputStage.onFinishedInputEvent(ViewRootImpl.java:4468)

    at android.view.inputmethod.InputMethodManager$PendingEvent.run(InputMethodManager.java:2435)

    at android.view.inputmethod.InputMethodManager.invokeFinishedInputEventCallback(InputMethodManager.java:1998)

    at android.view.inputmethod.InputMethodManager.finishedInputEvent(InputMethodManager.java:1989)

    at android.view.inputmethod.InputMethodManager$ImeInputEventSender.onInputEventFinished(InputMethodManager.java:2412)

    at android.view.InputEventSender.dispatchInputEventFinished(InputEventSender.java:141)

    at android.os.MessageQueue.nativePollOnce(MessageQueue.java)

    at android.os.MessageQueue.next(MessageQueue.java:325)

    at android.os.Looper.loop(Looper.java:142)

    at android.app.ActivityThread.main(ActivityThread.java:6541)

    at java.lang.reflect.Method.invoke(Method.java)

    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)

    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)

### Reproduced
1. Tap **_New Note_** floating action button.
2. Tap ***Toggle Checklist*** item in app bar.
3. Tap **_Enter_**/**_Return_** key twice.
4. Tap end of first line.
5. Tap **_Enter_**/**_Return_** key.
6. Notice crash.

Make|Model|Android Version|App Version
-|-|-|-
Google|Pixel 2|8.0.0|2.5.1

Start with AutoBullet.apply and follow its callers in NoteEditorFragment.attemptAutoList and afterTextChanged. Reproduce the sequence with an empty checklist item between two checklist items, then verify that pressing Enter inserts the new checklist item without an IndexOutOfBoundsException.

Written by the indexing model from the issue text.