meta-app-framework: add agl-driver to pipewire group

meta-app-framework: add agl-driver to pipewire group

- Update agl-session recipe to add agl-driver to pipewire
  group
- Apps in the new framework can access pipewire services
  if agl-driver is a part of pipewire group.

Bug-AGL: SPEC-4210

Signed-off-by: Ashok Sidipotu <ashok.sidipotu@collabora.com>
Change-Id: Iba3856006b36c0182aaa0e36e8e98f85d9c49af3
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/27100
Reviewed-by: Georgios Kiagiadakis <george.kiagiadakis@collabora.com>
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Tested-by: Jenkins Job builder account
ci-image-build: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account