refactor!: do not set primary theme on the CRUD new item button (#9817)

Author: web-padawan

packages/crud/src/vaadin-crud-controllers.js

@@ -42,7 +42,7 @@ export class ButtonSlotController extends SlotController {
     }
 
     // Respect default theme attribute set by the Flow counterpart
-    if (node === this.defaultNode && !node.hasAttribute('theme')) {
+    if (node === this.defaultNode && this.theme && !node.hasAttribute('theme')) {
       node.setAttribute('theme', this.theme);
     }
 

packages/crud/src/vaadin-crud-mixin.js

@@ -400,7 +400,7 @@ export const CrudMixin = (superClass) =>
       this.addController(this._gridController);
 
       // Init button controllers in `ready()` (not constructor) so that Flow can set `_noDefaultButtons`
-      this._newButtonController = new ButtonSlotController(this, 'new', 'primary', this._noDefaultButtons);
+      this._newButtonController = new ButtonSlotController(this, 'new', null, this._noDefaultButtons);
       this.addController(this._newButtonController);
 
       this._headerController = new SlotController(this, 'header', 'h3', {

packages/crud/test/crud-buttons.test.js

@@ -747,13 +747,13 @@ describe('crud buttons', () => {
         expect(button.textContent).to.equal('Add user');
       });
 
-      it('should set theme attribute of the new item button when marked as a default', async () => {
+      it('should not set theme attribute on the new item button when marked as a default', async () => {
         button._isDefault = true;
 
         crud.appendChild(button);
         await nextRender();
 
-        expect(button.getAttribute('theme')).to.equal('primary');
+        expect(button.hasAttribute('theme')).to.be.false;
       });
 
       it('should not change theme attribute of the new item button when marked as a default', async () => {

packages/crud/test/dom/__snapshots__/crud.test.snap.js

@@ -221,7 +221,6 @@ snapshots["vaadin-crud host default"] =
     role="button"
     slot="new-button"
     tabindex="0"
-    theme="primary"
   >
     New item
   </vaadin-button>