fix: equals of Optional and Non-Optional

src/main/java/cz/muni/fi/pa165/icehockeymanager/services/PlayerServiceImpl.java

@@ -45,7 +45,7 @@ public class PlayerServiceImpl implements PlayerService {
 
     @Override
     public void removeTeamFromPlayer(Player player, Team team) {
-        if(!player.getTeam().equals(team)){
+        if(player.getTeam().isEmpty() || !player.getTeam().get().equals(team)){
             throw new PlayerNotInTeamException("Player not in this team");
         }
         player.setTeam(null);