feat(forms): add markAllAsTouched() to AbstractControl (#26812)

Add functionality to mark a control and its descendant controls as touched

Closes #19400

PR Close #26812

packages/forms/src/model.ts

@@ -364,6 +364,16 @@ export abstract class AbstractControl {
     }
   }
 
+  /**
+   * Marks the control and all its descendant controls as `touched`.
+   * @see `markAsTouched()`
+   */
+  markAllAsTouched(): void {
+    this.markAsTouched({onlySelf: true});
+
+    this._forEachChild((control: AbstractControl) => control.markAllAsTouched());
+  }
+
   /**
    * Marks the control as `untouched`.
    *