Change the index of enhanced_4g_lte

The carrier app can hide this preference screen by set the carrier
config file and we don't want the settings index this preference screen
when it's hidden. This CL adds this key into non-indexable key list when
the preference screen is hidden.

Bug: 62976860
Test: TeleServiceTests
Change-Id: I72728ada7c2080ee13798bb3563b256e3f768b3f
3 files changed