wifi: mac80211: add kunit tests for public action handling

Check the logic in ieee80211_drop_unencrypted_mgmt()
according to a list of test cases derived from the
spec.

Reviewed-by: Benjamin Berg <benjamin.berg@intel.com>
Link: https://msgid.link/20231220151952.415232-4-benjamin@sipsolutions.net


Signed-off-by: Johannes Berg <johannes.berg@intel.com>