Only deactivate activated connections in wifi_nmcli_test.py (BugFix)#2246

Jefferyyen wants to merge 4 commits intocanonical:maincanonical/checkbox:mainfrom

Jefferyyen:fix/wifi-nmcli-down-only-activatedJefferyyen/checkbox:fix/wifi-nmcli-down-only-activatedCopy head branch name to clipboard