1. Code refactor 2. Replace ImsManager#isNonTtyOrTtyOnVolteEnabled() by combination of TelecomManager#getCurrentTtyMode() and ImsMmTelManager#isTtyOverVolteEnabled() Bug: 140542283 Test: m RunSettingsRoboTests -j ROBOTEST_FILTER=Enhanced4gBasePreferenceControllerTest Test: m RunSettingsRoboTests -j ROBOTEST_FILTER=Enhanced4gLteSliceHelperTest Change-Id: I5ea5978529a7ae9a63161caca22fb29102f24150