test: using yarn instead of npm

.github/workflows/playwright.yml

@@ -12,7 +12,7 @@ jobs:
         with:
           node-version: 18
       - name: Install dependencies
-        run: npm ci
+        run: yarn install --frozen-lockfile
       - name: Install Playwright Browsers
         run: npx playwright install --with-deps
       - name: Run Playwright tests