Add flash error message for invalid orgs

- Flash message displays when an org is not present in orgs table AND does not pass ROR validation
- Add request.present? to message condition in order for controller tests to work properly

Author: momo3404

app/controllers/contributors_controller.rb

@@ -122,6 +122,15 @@ def process_org(hash:)
     # Check if entered org has a valid ROR
     # If so, allow creation
     allow = validate_ror(hash)
+
+    # If org ROR cannot be validated, then contributor org is invalid
+    # Only trigger flash during a real request (tests calling this method directly have no request object)
+    if !allow && request.present?
+      flash[:alert] =
+        _('Invalid contributor affiliation. Please double check that your organisation does not appear in the list ' \
+          'in a slightly different form.')
+    end
+
     org = org_from_params(params_in: hash,
                           allow_create: allow)