updated run_tests to not use venv in the app if VIRTUAL_ENV is set
updated run_tests to not use venv in the app if VIRTUAL_ENV is set

alphagov/notifications-admin,gov-cjwaszczuk/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,gov-cjwaszczuk/notifications-admin,gov-cjwaszczuk/notifications-admin,gov-cjwaszczuk/notifications-admin