Update Bluetooth codec related strings

The settings related to Bluetooth codec selection
are actually triggers. Updated the corresponding
strings to reflect that.

Bug: 67682722
Test: Manual - examined the result UI
      runtest systemui
      make -j40 RunSettingsRoboTests
      make -j40 RunSettingsLibRoboTests
Change-Id: I872414f7620931a67b028c2997b0740ae3a45986