Handle test framework dependencies in required packages

[psss]

Instead of installing test framework dependencies during the essential requires, let's handle them under the required packages as they are not needed before the actual test execution. This prevents having to provide an explicit order when enabling the epel repository on centos-stream to run beakerlib tests.

Fix #4796.

Pull Request Checklist

• implement the feature
• write the documentation
• extend the test coverage
• include a release note

[gemini-code-assist]

Code Review

This pull request updates the prepare step to use collected_requires instead of collected_essential_requires for test framework requirements. Use tmt.base.core.assert_simple_dependencies to ensure requirements are simple dependencies and to provide better error messages.

[gemini-code-assist]

Use tmt.base.core.assert_simple_dependencies to ensure that test framework requirements are simple dependencies, maintaining consistency with how test.require and test.recommend are handled in the same loop. This also provides a more descriptive error message if a non-simple dependency is encountered.

                collected_requires[guest].dependencies += tmt.base.core.assert_simple_dependencies(
                    test.test_framework.get_requirements(test, self._logger),
                    'After beakerlib processing, tests may have only simple requirements',
                    self._logger,
                )

[LecrisUT]

• Nit: Can move the snippet next to the collected_requires?
• What about the checks?

[psss]

Simple plan and test to verify:

/plan:
    discover:
        how: fmf
    provision:
        how: container
        image: centos:stream9
    prepare:
        how: feature
        epel: enabled
    execute:
        how: tmt

/test:
    test: . /usr/share/beakerlib/beakerlib.sh && rlJournalStart && rlJournalEnd
    framework: beakerlib