Disable pull_request and push triggers in nightly workflow (#3742)

Disable until the next release cycle.

Author: svekars

.github/workflows/build-tutorials-nightly.yml

@@ -15,12 +15,13 @@ name: Build tutorials (nightly/test)
 # download the binaries in .jenkins/build.sh.
 on:
   # Only main branch for now. Uncomment the below line to enable it on PRs.
-  pull_request:
+  # pull_request:
 
   # Comment out the below line to disable on the main branch
-  push:
-    branches:
-      - main
+  # push:
+  #  branches:
+  #    - main
+  workflow_dispatch:
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.sha }}-${{ github.event_name == 'workflow_dispatch' }}-${{ github.event_name == 'schedule' }}