test: update test with new class name

Author: deiteris

test/api-body-document.test.js

@@ -264,7 +264,7 @@ describe('ApiBodyDocumentElement', () => {
 
         it('Narrow style is applied to the URI title', () => {
           element.style.setProperty('--arc-font-subhead-narrow-font-size', '16px');
-          const title = element.shadowRoot.querySelector('.table-title');
+          const title = element.shadowRoot.querySelector('.heading3');
           const fontSize = getComputedStyle(title).fontSize;
           assert.equal(fontSize, '16px');
         });