fix(audio): make overlay PipeWire setup idempotent to avoid RB8 rerun freezes

On overlay builds (audioreach modules present), setup_overlay_audio_environment()
was restarting pipewire every run, which can fail/hang on RB8 after the first
successful setup until reboot.

Make overlay setup idempotent:
- avoid unconditional pipewire restart on subsequent runs
- guard systemctl/wpctl calls with timeouts to prevent freezes
- keep DMA heap permission setup but fail only on real errors
- add readiness polling to confirm PipeWire is usable

This removes flaky FAILs on repeated AudioRecord runs on RB8 overlay images.

Signed-off-by: Srikanth Muppandam <smuppand@qti.qualcomm.com>

Author: smuppand