Fix a11y label for LE Audio Battery

Before fix, "Left" & "Right" are in the same LinearLayout, not grouped
with battery info.

After fix, "Left" & "100% battery" are grouped together.

Bug: 229042138
Test: manual test when Talkback enabled
Change-Id: Ieb35ef992f62040f14ed878515d63f6edb2559f6
3 files changed