Fixed integration test

[lslezak]

Problem

• The integration test was failing
• https://github.com/openSUSE/agama/actions/runs/7395724982/job/20119447308

Solution

During debugging I found several problems:

• The agama.gemspec file calls git describe --tags, that does not work when the Git checkout contains only the last commit and no history. Fixed by fetching the Git repository with full history. (Note: There is no significant slow down, even with the full history the Git repository is fetched in 2 seconds.)
• The Cockpit service is started manually but later systemd wants to start it as a service dependency and that fails because the port 9090 is already taken.
• The products directory now contains several YAML product files, delete all of them except the Tumbleweed configuration.
• Increased the timeout in the tests, refreshing the Tumbleweed repository sometimes might take more time and in that case the test fails because of time out.
• More precise "Back" button specification in root_password.spec.ts test, that text matched the "Czech (extra backslash)" text in the keyboard selection menu. (Playwright by default does a partial case-insensitive match, short texts might accidentally match a substring in longer texts.)
• Added some more debugging steps in the workflow to get more details when something fails

Testing

• The integration test now passes without problems
• https://github.com/lslezak/agama/actions/runs/7407057992/job/20152559638

[dgdavid]

LGTM, thanks for taking care.

Worth to mention what we've talked in IRC,

<dgdavid> lslezak: why only TW?
<dgdavid> lslezak: I mean, what if we want to set an integration test for another product?
<lslezak> dgdavid: so far the tests are simple and they check the same things regradless of the selected product
<lslezak> dgdavid: we can test more products after adding more tests