bluetooth.conf: open secondary access to pipewire

bluetooth.conf: open secondary access to pipewire

with out having a secondary access to pipewire(export core), wireplumber creates
bluetooth device objects as well as access the existing pipewire objects using
the same pipewire connection, which can some times create race conditions.

Enable export core, so that wireplumber bluetooth monitor has access to both the
regular core and the export core.

Bug-AGL: SPEC-4750
Change-Id: I0db9b276ecd6972294c36722bf5a31c5ac00f186
Signed-off-by: Ashok Sidipotu <ashok.sidipotu@collabora.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/28639
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>