I have the same issue using HE's built-in driver; it doesn't report wet/dry events for my leakSmart sensors.
It's been a long time since I got these working on HE; I dimly recall not finding any resolution in the forum when I ran into this issue a few years ago. I do know that I had mailed my sensors to leakSmart for a firmware update (originally they had only a few months battery life; after the update they go more than a year without battery changes). For the record, my sensors show these firmware details:
- firmwareMT: 113B-07D1-00000034
- manufacturer: WAXMAN
- model: leakSMART Water Sensor V2
- softwareBuild: 00000034
As I recall, I got them working on HE byporting the driver you posted with the usual ST>HE adjustments (see: App and driver porting to Hubitat - 
Developers - Hubitat ) That fixed wet/dry event reporting for my sensors.
Also, to get temperature reporting working correctly, line 340 needs to be replaced with:
def value = getTemperature(swapEndianHex(descMap.value))
