Salam alaikum, my question is if a person "other than my wife" seeing the "Awrah" of me while I am in wudu. Does this invalidate my wudu?
First of all you could even perform wudu' naked (for example while performing ghusl) and it won't invalidate your wudu'. (See Which things break the wudu?)
As exposing the 'awrah doesn't invalidate wudu', but might be considered as a sin if done intentionally.
If anybody (non-Mahram) is looking at you while you do so intentionally he/she might be sining and should repent. Of course you too should avoid doing this in public and take the necessary care.
This is Based on verses like:
O children of Adam, We have bestowed upon you clothing to conceal your private parts and as adornment. But the clothing of righteousness - that is best. That is from the signs of Allah that perhaps they will remember. (7:26)
Tell the believing men to reduce [some] of their vision ... (24:30)
And tell the believing women to reduce [some] of their vision ... (24:31)
I said: Messenger of Allah, from whom should we conceal our private parts and to whom can we show? He replied: conceal your private parts except from your wife and from whom your right hands possess (slave-girls). I then asked: Messenger of Allah, (what should we do), if the people are assembled together? He replied: If it is within your power that no one looks at it, then no one should look at it. I then asked: Messenger of Allah if one of us is alone, (what should he do)? He replied: Allah is more entitled than people that bashfulness should be shown to him.
(Sunan abi Dawod and Jami' at-Tirmidhi)