TelecomAccountRegistry should be consistent in operator name retrieval

Currrently, the logic for deriving the operator name is different
between the single sim case and dual sim case. Minor update to make sure
the logic for these two scenarios are in par with one another.

Bug: 239730565
Test: Manual
Change-Id: Icef3cb269a82786cafb50508d41a54a185587ee6
1 file changed