build: add tests to workflow_dispatch group for testing purposes

.github/workflows/backend-tests.yaml

@@ -5,6 +5,7 @@ on:
     branches: [main, development, automated-testing]
   pull_request:
     branches: [main, development]
+  workflow_dispatch:
 
 jobs:
   test:
@@ -20,4 +21,4 @@ jobs:
           python -m pip install --upgrade pip
           pip install -r ./backend/requirements.txt
       - name: Execute tests
-        run: python ./backend/manage.py test
+        run: python ./backend/manage.py test