Load external library in the default namespace

Aptx and aptx-Hd are both loaded from system_ext.
In order to load their dependencies from a compatible environement we
need to set the lib as a requirredLibs in the manifest

Fix: 231967310
Test: atest net_test_stack_a2dp_native
Test: Log analyze after bluetooth boot
Tag: #refactor
Ignore-AOSP-First: Apex only on tm and below
Merged-In: I084536b137adde5754eb98d80012bc7fdad1af74
Change-Id: I084536b137adde5754eb98d80012bc7fdad1af74