fix: Restore demo-v4 branch in workflow triggers

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Rafi-Microsoft

.github/workflows/test.yml

@@ -4,6 +4,7 @@ on:
   push:
     branches:
       - main
+      - demo-v4
       - dev-v4
     paths:
       - 'src/backend/**/*.py'
@@ -22,6 +23,7 @@ on:
       - synchronize
     branches:
       - main
+      - demo-v4
       - dev-v4
     paths:
       - 'src/backend/**/*.py'