fix tests

Author: vursen

packages/grid/test/grid-test-styles.js

@@ -11,6 +11,7 @@ style.textContent = css`
     max-width: none;
     -webkit-font-smoothing: antialiased;
     -moz-osx-font-smoothing: grayscale;
+    --vaadin-grid-row-border-width: 0px;
   }
 
   vaadin-grid::part(cell) {

packages/grid/test/row-details.test.js

@@ -119,7 +119,7 @@ describe('row details', () => {
       const bounds = cells[1].getBoundingClientRect();
       expect(bounds.top).to.be.closeTo(cells[0].getBoundingClientRect().bottom, 1);
       expect(bounds.left).to.equal(cells[0].getBoundingClientRect().left);
-      expect(bounds.right).to.equal(grid.$.items.getBoundingClientRect().right);
+      expect(bounds.right).to.equal(cells[0].getBoundingClientRect().right);
       expect(bounds.bottom).to.be.closeTo(bodyRows[2].getBoundingClientRect().top, 1);
       expect(bounds.height).to.be.above(10);
     };