[Settings] Remove access to getSimOperator() API

Replace getSimOperator() by having SubscriptionInfo
from ProxySubscriptionManager#getActiveSubscriptionInfo().

Bug: 144263441
Test: Manual
Test: make RunSettingsRoboTests -j ROBOTEST_FILTER=ApnEditorTest
Change-Id: I132b352dfb50a9cd3a2ddd21b347177ac0332740
Merged-In: I25cc9dc0912564b8d6f8b23b53f3eb20a51eea32
2 files changed