leaudio: Update HAL audio session on metadata update

With this patch, LeAudio module will update HAL session on metadata
change callback and not on audio resume.

This is in order to have session ready as soon as possible

Bug: 150670922
Tag: #feature
Sponsor: jpawlowski@
Test: manual

Change-Id: Iaf8b843fee8045a59836e986d7264da373714058