Show "Disconnect" on forget button for ephemeral network

For app or carrier initiated wifi connections (i.e all "ephemeral networks"),
the detailed page of settings should show "Disconnect" instead of "Forget".

Bug: 123892605
Test: atest WifiDetailPreferenceControllerTest
Change-Id: I1ee7f45ea12fe2ab9ca35cab77de0b1d67efc1db