text-editor: stopTrigger() with no active trigger throws a TypeError

[john-traas]

The trigger plugin's state.apply (src/components/text-editor/prosemirror-adapter/plugins/trigger/factory.ts) reacts to the stopTrigger transaction meta by building a triggerStop event without guarding activeTrigger === null. Calling textEditor.stopTrigger() twice, or after the trigger has already ended for another reason, throws inside getTriggerEventDetail (trigger.character on null).