TEST: run optional tests

Signed-off-by: Lennart Jern <lennart.jern@est.tech>

.github/workflows/e2e-test-optional-periodic.yml

@@ -4,6 +4,9 @@ on:
   schedule:
     # Run every day at 04:20 UTC (it is recommended to avoid running at the start of the hour)
     - cron: '20 4 * * *'
+  pull_request:
+    branches:
+    - 'main'
 
 permissions: {}