Rule "ion-item requires an ion-label component" does not work with two labels

[NiklasMerz]

The rule ion-item requires an ion-label component is throwing errors for items with two or more labels.

Test to reproduce:

Add to first describe block in "ionItemIonLabelRequired.spec.ts"

it('should work with two ion-label children', () => {
      let source = `
      @Component({
        template: \`
          <ion-item>
            <ion-thumbnail slot="start">
              <img src="http://pngimg.com/upload/dog_png2402.png">
            </ion-thumbnail>
            <ion-label *ngIf="something">Dog</ion-label>
            <ion-label *ngIf="!something" >Dog</ion-label>
          </ion-item>
        \`
      })
      class Bar{}
        `;
      assertSuccess(ruleName, source);
    });