Remove unused qtcompositor packagegroup

Remove unused qtcompositor packagegroup

Remove qtcompositor packagegroup that was missed in initial cleanup
commit.

Bug-AGL: SPEC-5152

Change-Id: I889dd42ded600d47a5e76c4723cc458ce5e9145e
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl-demo/+/30118
Tested-by: Jenkins Job builder account
ci-image-build: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account
Reviewed-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>