Cache python and node build for playwright run on the same commit hash

[thinkh]

Currently, when a PR is flagged as ready for review we are automatically running the "Build repository / build / Node, Python, Playwright (pull_request)" workflow for the last commit hash. Once the reviewer approves the PR the workflow "Build repository / build / Node, Python, Playwright (pull_request_review)" will run on the exact same commit hash.

In both cases we are running the same setup (installing dependencies, yarn build, applying DB migrations, ...). Given the same commit hash, we could speed up the setup by caching the results of the first workflow and skip the compile and testing for the second workflow run.