Lexical: Aligned new empty item behaviour for nested lists

- Makes enter on empty nested list item un-nest instead of just creating
  new list items.
- Also updated existing lists tests to use newer helper setup.

resources/js/wysiwyg/lexical/core/__tests__/utils/index.ts

@@ -776,6 +776,7 @@ export function dispatchKeydownEventForNode(node: LexicalNode, editor: LexicalEd
     key,
   });
   nodeDomEl?.dispatchEvent(event);
+  editor.commitUpdates();
 }
 
 export function dispatchKeydownEventForSelectedNode(editor: LexicalEditor, key: string) {

resources/js/wysiwyg/lexical/list/LexicalListItemNode.ts

@@ -271,11 +271,18 @@ export class ListItemNode extends ElementNode {
   insertNewAfter(
     _: RangeSelection,
     restoreSelection = true,
-  ): ListItemNode | ParagraphNode {
+  ): ListItemNode | ParagraphNode | null {
 
     if (this.getTextContent().trim() === '' && this.isLastChild()) {
       const list = this.getParentOrThrow<ListNode>();
-      if (!$isListItemNode(list.getParent())) {
+      const parentListItem = list.getParent();
+      if ($isListItemNode(parentListItem)) {
+        // Un-nest list item if empty nested item
+        parentListItem.insertAfter(this);
+        this.selectStart();
+        return null;
+      } else {
+        // Insert empty paragraph after list if adding after last empty child
         const paragraph = $createParagraphNode();
         list.insertAfter(paragraph, restoreSelection);
         this.remove();

resources/js/wysiwyg/services/__tests__/keyboard-handling.test.ts

@@ -48,7 +48,6 @@ describe('Keyboard-handling service tests', () => {
         expect(lastRootChild).toBeInstanceOf(DetailsNode);
 
         dispatchKeydownEventForNode(detailsPara, editor, 'ArrowDown');
-        editor.commitUpdates();
 
         editor.getEditorState().read(() => {
             lastRootChild = $getRoot().getLastChild();
@@ -79,10 +78,7 @@ describe('Keyboard-handling service tests', () => {
         expect(lastRootChild).toBeInstanceOf(DetailsNode);
 
         dispatchKeydownEventForNode(detailsPara, editor, 'Enter');
-        editor.commitUpdates();
-
         dispatchKeydownEventForSelectedNode(editor, 'Enter');
-        editor.commitUpdates();
 
         let detailsChildren!: LexicalNode[];
         let lastDetailsText!: string;
@@ -115,7 +111,6 @@ describe('Keyboard-handling service tests', () => {
         });
 
         dispatchKeydownEventForNode(listItemB, editor, 'Tab');
-        editor.commitUpdates();
 
         editor.getEditorState().read(() => {
             const list = $getRoot().getChildren()[0] as ListNode;