The cabin air filter is higher and to the right of where the condensate is backing up and leaking - but it was a good idea to check it because if it gets wet, it could also grow some mold & mildew and generally make things more uncomfortable for you.
Open your hood and look for a right angle rubber elbow coming out of the firewall on the passenger side leading to a tube going straight down along the firewall and opening about level with the corner of the firewall and the floorboard area. A shop would usually use a compressed air blast but you can also insert a very narrow cleaning brush or a long pipe cleaner (can be bought in rolls as well as the more familiar 6" cut lengths). I like gun cleaning brushes soaked in bleach to clean out tubing & hoses. A nylon brush made for a .22 would work for this tubing.