[SB][Carrier] Don't announce "selected" for a11y lockscreen carrier text

Similar solution as I0083c24bd7b0ead98ea2f157fa4f411e173d5e12.

Fixes: 319390556
Flag: EXEMPT bugfix
Test: With TalkBack on, verify carrier text on lockscreen is always
marqueeing. Focus on carrier text -> verify TalkBack doesn't include
"selected" in the announcement

Change-Id: Ib37b9e29bf3907547f05e7fbd6c14846531f75d3