25237 needs a follow up work

[stas00]

Looks like the modified check_config_can_be_init_without_params in #25237 broke the yet unmerged #24796

I patched it to skip these tests here so that we could merge it here 906485b
but most likely this needs to be fixed yet.

FWIW, this part doesn't fail:

    def check_config_can_be_init_without_params(self):
        config = self.config_class()
        self.parent.assertIsNotNone(config)

The updated test in this PR expects the config class to fail if it's a composition, but in the case of Idefics it succeeds (not sure why it should fail).

[stas00]

resolved in 2e37e6c