[bug] tests broken for tabs

[zeroedin]

Wasn't quite finished working on fixing tabs tests when a PR was merged. main branch now has the broken test and ❌ on test build.

Will close this issue with a new PR.

elements/pf-tabs/test/pf-tabs.spec.ts:159:14 - error TS18048: 'snapshot.children' is possibly 'undefined'.

159       expect(snapshot.children.find(x => x.role === 'tabpanel')?.name).to.equal('Database');
                 ~~~~~~~~~~~~~~~~~

elements/pf-tabs/test/pf-tabs.spec.ts:175:13 - error TS2488: Type 'A11yTreeSnapshot[] | undefined' must have a '[Symbol.iterator]()' method that returns an iterator.

175       const [disabledTab] = snapshot.children;
                ~~~~~~~~~~~~~

elements/pf-tabs/test/pf-tabs.spec.ts:176:51 - error TS7006: Parameter 'x' implicitly has an 'any' type.

176       const tabButton = disabledTab.children.find(x => x.role === 'button')!;