Prevent anything being scheduled on the manual pipelines

Author: Steve Pfister

eng/pipelines/runtime-staging.yml

@@ -22,13 +22,14 @@ trigger:
     - SECURITY.md
     - THIRD-PARTY-NOTICES.TXT
 
-schedules:
-  - cron: "0 7,19 * * *" # run at 7:00 and 19:00 (UTC) which is 23:00 and 11:00 (PST).
-    displayName: Runtime-staging default schedule
-    branches:
-      include:
-      - main
-    always: false # run only if there were changes since the last successful scheduled run.
+- ${{ if not(eq(variables['Build.DefinitionName'], 'runtime-staging-manual')) }}:
+  schedules:
+    - cron: "0 7,19 * * *" # run at 7:00 and 19:00 (UTC) which is 23:00 and 11:00 (PST).
+      displayName: Runtime-staging default schedule
+      branches:
+        include:
+        - main
+      always: false # run only if there were changes since the last successful scheduled run.
 
 pr:
   branches: