chore: refactor are_unis_active(self, switches) and get_interface_from_switch(uni, switches)

[viniarck]

• Refactor are_unis_active(self, switches: dict), this shouldn't take switches, LinkProtection class already has access to it via self._controller.switches.

• UNI interfaces that is get from controller should be get from uni.interface since UNIs have been instantiated in this class, it can access directly the existing ref no need to get the interface again via switches ref. As a consequence get_interface_from_switch can also be removed.

[viniarck]

There are too many PRs landing on mef_eline changing these adjacent parts, I'll leave this for a next moment to avoid creating additional git conflicts while other higher priority PRs are still landing. This is a low hanging fruit that only impacts code readability so can be done later when the time is right.