drm/ci: fix merge request rules

drm/ci: fix merge request rules

Merge request pipelines were only created when changes
were made to drivers/gpu/drm/ci/, causing MRs that
didn't touch this path to break. Fix MR pipeline rules
to trigger jobs for all changes.

Run jobs automatically for marge-bot and scheduled
pipelines, but in all other cases run manually. Also
remove CI_PROJECT_NAMESPACE checks specific to mesa.

Fixes: df54f04f2020 ("drm/ci: update gitlab rules")
Signed-off-by: Vignesh Raman <vignesh.raman@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Helen Koike <helen.fornazier@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250228132620.556079-1-vignesh.raman@collabora.com