Use subcontext for APEX configs from /{vendor, odm}

Instead of using config file path, use APEX's preinstalled path to
determine whether to use subcontext or not for APEX configs.

Bug: 232021354
Test: CtsInitTestCases, CtsBluetoothTestCases
Change-Id: Iba603f09602f0bec3113e2be3d15c62055c09e72