npcap uninstall fails with wlanhelper in interactive mode

[packetfoo]

This is just a minor thing - if npcap is reinstalled it de-installs the previous version. This fails if wlanhelper.exe is still running in interactive mode, for obvious reasons. Maybe a check could be added to see if wlanhelper is still running and prompting for a close, just like it does for wireshark.exe?

[dmiller-nmap]

As the commit message indicates, this is not a permanent fix, but it's a step in the right direction.

[dmiller-nmap]

Npcap's installer and uninstaller now properly check for processes which are using Npcap resources (DLLs and driver handles). These changes and all related bugfixes have been final since Npcap 1.20.