fix: fix nafath backend flow (#437)

Co-authored-by: Muhammad Faraz  Maqsood <[email protected]>

openedx/core/djangoapps/user_authn/views/login.py

@@ -129,7 +129,7 @@ def _get_user_by_email_or_username(request, api_version):
     login_fields = ['email', 'password']
     if is_api_v2:
         login_fields = ['email_or_username', 'password']
-    if request.POST.get('is_nafath_user', False):
+    if request.POST.get('is_nafath_user', False) and request.POST.get('trans_id', ""):
         login_fields.remove('password')
 
     if any(f not in request.POST.keys() for f in login_fields):
@@ -241,7 +241,7 @@ def _authenticate_first_party(request, unauthenticated_user, third_party_auth_re
     if not third_party_auth_requested:
         _check_user_auth_flow(request.site, unauthenticated_user)
 
-    if request.POST.get('is_nafath_user', False):
+    if request.POST.get('is_nafath_user', False) and request.POST.get('trans_id', ""):
         return authenticate(
             username=username,
             request=request