Refine the map between audio attribute and LE audio context type

The audio attribute content type is not clear for the usage. So the
patch remove content check as the stream not configured to
conversational, and based on the usage to set the LE audio context type
only. It contains the following setting,
1. Add support navigation audio to Instructional
2. Add support calll assistant to Conversationoal
3. only check the USAGE_MEDIA for Media
4. If the usage is UNKOWN, set it default too Meida

Bug: 228924591
Test: start navigation as music streaming, all the sound could be heard
Change-Id: I84e9bdeb27c18f3f81422726f6a4e47cb7fbd6da