ephemeral newtork
WifiConfiguration is only available when saved network. So ephemeral
newtork could not have wifi config to config wifi setting. In this
situation, making option be not selectable.
Bug: 122919564
Test: atest WifiPrivacyPreferenceControllerTest
Change-Id: I8a2a1c36ec6d41a6f912da29a8b17bc2e43d9a27