Display an explicit warning in the WiFi configuration menu if
the user selects the option to not validate the EAP server (i.e.
does not provide a CA certificate) in an EAP configuration.
BUG: 26686071
Change-Id: I73620b60defdcf40865f8c67d5de24b5dad636f8
TEST: Warning appears when the abovementioned option is selected.