Add multi browser tests + wabac.js update (#420)

Fidelity: Fix CSP issue with iframes in Firefox (via wabac.js 2.23.0)
Loading: Avoid unnecessary reloads of multiWACZ JSON, prune expired
multiWACZ collections

Testing improvements:
- add playwright multi browser tests with firefox and webkit
- add test of iframe replay with iframetest.wacz

deps: update to wabac.js 2.23.0
bump to 2.3.9

.github/workflows/integration.yaml

@@ -27,7 +27,7 @@ jobs:
         run: yarn build
 
       - name: Playwright Install Browsers
-        run: yarn playwright install
+        run: yarn playwright install --with-deps
 
       - uses: actions/setup-python@v4
         with: