ci: Don't run sanity job in forked pipelines
d4151f2e from !7926 (merged) was intended to only run the sanity job in pre-merge pipelines, but still left the definition as is-forked-branch-or-pre-merge. After removing the in-job check that it was actually running as part of an MR, it would run and fail in non-MR refs.
Signed-off-by: Daniel Stone daniels@collabora.com Fixes: d4151f2e ("ci: Run sanity job only in pre-merge pipelines")