This is what i did to Solve Moisture Detected Issue in USB Charging Port and it seems to be working in the meantime.

Steps to Get Rid of Moisture Detected in USB Charging Port Error in Samsung Galaxy Phones
- Plug in your Samsung Phone to the charger (you will be notified that there is moisture detected)
- Restart your Samsung Phone (make sure not to remove the charging cable)
- Make sure it shows how long until full charge.
- You have by successfully by passed the moisture detected error from Samsung phone.

Pro Tip to Avoid Moisture Detected Issue in Samsung Phones: Do not keep your phone too close to your mouth. Use an earphone or wireless earbuds, so that moisture does not go inside usb charging port. In case you are still facing this trouble, consider using wireless charger for a while until this issues gets solved.