Reverted test all notebooks github actions

.github/workflows/test_all_notebooks.yml

@@ -9,7 +9,6 @@ defaults:
 on:
   # Trigger the workflow on manual dispatch and once a week
   workflow_dispatch:
-  pull_request:
   schedule:
     - cron: '0 0 * * 0'
 
@@ -21,7 +20,7 @@ jobs:
       fail-fast: false  # Continue to run other builds despite a failure
       matrix:
         os: [ ubuntu-latest ]
-        python-version: [ '3.9', '3.10', '3.11' ]
+        python-version: [ '3.8', '3.9', '3.10', '3.11' ]
         include: # Run windows tests on only one python version
           - os: windows-latest
             python-version: '3.10' # torch 1.x not available on Windows for Python 3.11