Lots of people run with no WIF with no problem. Its up to you really. If you dont have a problem running without it I'd get a WIF plug and just tape up the wires. If you want to run it you should be able to splice them back together..
It will not throw a CEL or store a code, if it is not connected.
I have never heard of one working when they had water in the filter anyway. The filter would have to be half full of water, to close the reed contacts, for the light to come on. Probably would quit running long before that happened.
Just get a aluminum plug, available from several vendors.
Mine tells me that I have water in my fuel alot because the little float that floats on the water(if there ever is any) is always getting jammed up. IMO they should have left it as a solid bottom filter so it doesn't dump out of two ends everytime you remove a filter..it's afaik of a design to say the least.