Refactor tooltip and reviews-stars libraries; update CI workflow

- Updated the CI workflow to build and test only the "reviews-stars" project.
- Removed unnecessary test files for the "reviews-stars" and "tooltip" libraries.
- Changed the export of TooltipComponent from default to named export.

libs/reviews-stars/src/lib/reviews-stars.spec.ts

@@ -1,7 +0,0 @@
-import { reviewsStars } from './reviews-stars';
-
-describe('reviewsStars', () => {
-  it('should work', () => {
-    expect(reviewsStars()).toEqual('reviews-stars');
-  });
-});

libs/tooltip/src/lib/tooltip.component.ts

@@ -13,7 +13,7 @@ import { Placement } from './models/placement.enum';
 import { basicStyles, positioning, variables } from './styles';
 
 @customElement('z-tooltip')
-export default class TooltipComponent extends LitElement {
+export class TooltipComponent extends LitElement {
   /** Private variables */
   private readonly _visibilityController = new VisibilityController(this);
   private readonly _positionController = new PositionController(this);

libs/tooltip/src/lib/tooltip.spec.ts

@@ -1,7 +0,0 @@
-import { tooltip } from './tooltip.component';
-
-describe('tooltip', () => {
-  it('should work', () => {
-    expect(tooltip()).toEqual('tooltip');
-  });
-});