Mobile network settings: Keep current tab visible after screen rotation

Keeps the current tab visible in mobile network settings after a screen
rotation. Previous behavior was to always revert back to initially shown
tab.

This prevents erratic behavior in dialog preferred network type if it is
open during screen rotation.

Bug: 117144283
Test: Manual
Change-Id: I38f9525f39d42dfb83fadabb216b6ac6396618c5
1 file changed