maybe: cache playwright installs in github actions

[elbotho]

https://playwrightsolutions.com/playwright-github-action-to-cache-the-browser-binaries/

[Entkenntnis]

we can switch the waiting script with the install - this way the install time would not affect the moment the tests start. This could save us ~20 seconds per test run

I'm seeing nothing against it and should have probably set this up this way in the beginnning