Support multiple CA certs when editing a saved Wifi network.

SSID with multiple CA certs can only be added programmtically. However it
can still be edited in the UI by long-pressing the item when currently
connected to the network. This change makes sure the UI shows up with
 meaningful indications that the SSID is configured with multiple CA certs.

Bug: 22547958
Change-Id: I5d42313efb141db521dd09ff3fbc520915b6fb79