This liquid (urine) is considered wadi and not madhi. Wadi is defined as a thick white cloudy secretion that has no smell, and usually follows urination and can sometimes come before it. Whereas madhi is a clear thin secretion that exits in small amounts (f: when having a lustful thought or when making a lustful glance). [Maraqi al-Falah 1:150]
Both of these secretions are considered filth and necessitate wudu without ghusl. [Dur al-Mukhtar 1:111]
If a trace of any of these two filths, not amounting to the area of a dirham (approx. 5 centimetres in diameter), affects one’s clothing, then it would be recommended for one to remove it.