ci/valve-farm-rules: allow running jobs from outside the mesa namespace

This has been requested as it breaks the stress and uprev tools, so
the requirement was dropped in the Valve farms. This commit mirrors
the change in Mesa.

Signed-off-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21872>

.gitlab-ci/test-source-dep.yml

@@ -233,11 +233,6 @@
   rules:
     - if: '$VALVE_FARM == "offline"'
       when: never
-    # The Valve CI Farm uses allow lists for projects/users to prevent abuse,
-    # so only enable automatic testing when running in the context of Mesa to
-    # prevent failures in forks.
-    - if: '$CI_PROJECT_NAMESPACE != "mesa"'
-      when: never
 
 .austriancoder-farm-rules:
   rules: