That air filter housing has a hose connected to it that goes to that catch can for the breather overflow that I described earlier.
That hose on the air filter housing doesn't need to be attached, except for air pollution control testing. It can be pulled off the air filter housing, and you can take the oily air filter out and clean the oil out of the air filter housing, and put a new air filter in. Then the oil won't get into the air filter again anymore.
But you need to empty that catch can, because it is full of oil, and it's going to continue to overflow out that hose, and get oil on other parts of the bike.
You must empty that catch can of oil.