Add dependency on pulseaudio until echo cancellation is supported in pipewire

More details here https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/4170

This needs Mobian-team/meta-mobian!21 (merged)

We will also need to install / manage systemd presets like this commit from pureos crimson https://source.puri.sm/Librem5/librem5-base/-/commit/e55f39d8cb1137bfec68badec7da91fb88fc7a18