Added a step for packaging IDE which runs integration tests.
This is an additional step, not a job, because here I'm sure the package will exist and won't be built unnecessarily twice. Technically I could make a job downloading it from GH action, but didn't want to invest time to rust scripts. Once Bazel will be fully introduced, the integration test will be improved.
# Important Notes
Fixes#8487
A stub for integration tests to be run locally; part of #8487
To run tests, you need to:
1. Build IDE package: `./run ide build`
2. set ENSO_TEST_USER and ENSO_TEST_USER_PASSWORD to some working credentials (I used my personal account, but there will be also test user soon)
3. run `corepack pnpm -r --filter enso exec playwright test`
The tests are run with a separate projects directory set up in tmpdir, so any local workspace dir is not affected.
The only test so far just checks if it's possible to log in and create a new project.
