The Network Select shows wrong operator name

 It get the empty subscriptionInfoList from
 SubscriptionManager#getAccessibleSubscriptionInfoList, so the UI
 shows default subId's operator.
 Since this item appears, when sim is active, using
 getActiveSubscriptionInfoList is enough.

 - https://screenshot.googleplex.com/9aHtDVpnYQBsiQr

Bug: 182020952
Test: atest MobileNetworkUtilsTest
atest OpenNetworkSelectPagePreferenceControllerTest

Change-Id: I0d86ec41236a0d1be657ccd57fd0cf90f96b8b89