tests: drivers: counter: fix skip tests check

When running this test with multiple counter instances enabled that
support different capabilities, if one of the instances does not
support the test required capabilities, the test will be
immediately skipped not giving the chance to run to the subsequent
instances.

Fix this by marking the test as skipped, only of all counter instances
under test were skipped.

Fixes #74358

Signed-off-by: Manuel Argüelles <marguelles.dev@gmail.com>