fix(ci): run build-and-push when check-new-commits is skipped (#2408)

check-new-commits runs only on the schedule, so push and workflow_dispatch
runs skip it. build-and-push had no status function in its condition, so
GitHub added an implicit success(), which counts that skipped ancestor and
skips the job as well. Since #2185 dropped the always() guard that #1855
added, no push or manual run on main has built an image; only cron runs
have.

Use !cancelled() so the job runs whenever prepare succeeds and still stops
when the run is cancelled.

Author: irnb

.github/workflows/ci-build.yml

@@ -166,7 +166,9 @@ jobs:
   build-and-push:
     name: "Build ${{ matrix.program }}"
     needs: [prepare]
-    if: needs.prepare.result == 'success'
+    # check-new-commits is skipped on push and dispatch. Without a status
+    # function, the implicit success() sees that skip and skips this job too.
+    if: ${{ !cancelled() && needs.prepare.result == 'success' }}
     runs-on: ubuntu-latest
     environment: prod
     permissions: