Check ServiceState when showing dialog

When showing the dialog the first time cellular data is turned off from
QS, check if the data network is in service. If it's not, do not believe
the carrier name and use a generic string instead.

Test: atest NetworkControllerDataTest
Bug: 156238588
Change-Id: Iee8091921ecdaba0c18f67080348240b8b8f67a7
Merged-In: Iee8091921ecdaba0c18f67080348240b8b8f67a7
(cherry picked from commit 15012a9a)