meta-app-framework: tweak agl-driver definition

meta-app-framework: tweak agl-driver definition

Tweak agl-driver user definition in agl-session recipe to ensure
it is a member of the video and display groups (the latter has
been added back to the static group file).  This is required to
avoid agl-compositor startup failures on rcar3.  The display
group membership potentially could be dropped if we were to
bbappend rcar3's gles-user-module recipe to tweak its udev rules.
For now, take the most straightforward approach.

Bug-AGL: SPEC-4161

Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: I7237ade5d8680655f17716ac048349a476eb5f29
Reviewed-on: https://gerrit.automotivelinux.org/gerrit/c/AGL/meta-agl/+/27060
Tested-by: Jenkins Job builder account
ci-image-build: Jenkins Job builder account
ci-image-boot-test: Jenkins Job builder account