agl-pipewire: update layer dependencies

agl-pipewire: update layer dependencies

meta-pipewire now requires meta-multimeda for the base pipewire
recipe, make sure that layer gets added when the agl-pipewire feature
is used.  This fixes builds without "agl-demo".

Bug-AGL: SPEC-5129

Change-Id: If054d63f8328607d2063e8168bc88f2b82b146db
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/30101
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
ci-image-boot-test: Jenkins Job builder account
Tested-by: Jenkins Job builder account
ci-image-build: Jenkins Job builder account