Our tests fail to test workflows

[markotoplak]

...except the Qt6 tests.

#6181 had a compatibility issue which we almost did not catch because only Qt6 tests were having problems.

The cause for this is that tox.ini for testenv includes:

    # Skip loading of example workflows as that inflates coverage
    SKIP_EXAMPLE_WORKFLOWS=True

These worfklows should be skipped only for the run that is actually used for coverage. So we should do the opposite, run example workflows everywhere except on a one specific (coverage) run.