fix(material/chips): remove button role from editable chips

Removes the button role from editable input chips. Fix accessibility
issue in ChipRow where the chip action element is mislabeled as a
button (angular#27106).

Fix angular#27106

src/material/chips/chip-row.html

@@ -10,7 +10,6 @@
 <span class="mdc-evolution-chip__cell mdc-evolution-chip__cell--primary" role="gridcell">
   <span
     matChipAction
-    [attr.role]="editable ? 'button' : null"
     [tabIndex]="tabIndex"
     [disabled]="disabled"
     [attr.aria-label]="ariaLabel"

src/material/chips/chip-row.spec.ts

@@ -256,14 +256,16 @@ describe('MDC-based Row Chips', () => {
         return chipNativeElement.querySelector('.mat-chip-edit-input')!;
       }
 
-      it('should set the role of the primary action based on whether it is editable', () => {
+      it('should set not set role of the primary action even if it is editable', () => {
         testComponent.editable = false;
         fixture.detectChanges();
         expect(primaryAction.hasAttribute('role')).toBe(false);
 
         testComponent.editable = true;
         fixture.detectChanges();
-        expect(primaryAction.getAttribute('role')).toBe('button');
+        // Test regression of bug where element is mislabeled as a button role. Element that does not perform its
+        // action on click event is not a button by ARIA spec (#27106).
+        expect(primaryAction.hasAttribute('role')).toBe(false);
       });
 
       it('should not delete the chip on DELETE or BACKSPACE', () => {