Removed get_user_first_name function

lms/djangoapps/discussion/rest_api/api.py

@@ -1882,7 +1882,7 @@ def get_course_discussion_user_stats(
     course_stats_response = get_course_user_stats(course_key, params)
 
     for user_stat in course_stats_response["user_stats"]:
-        user_stat["user_first_name"] = get_user_first_name(user_stat["username"])
+        user_stat["user_first_name"] = User.objects.get(user_stat["username"]).first_name
 
     if comma_separated_usernames:
         updated_course_stats = add_stats_for_users_with_no_discussion_content(
@@ -1907,13 +1907,6 @@ def get_course_discussion_user_stats(
         "results": serializer.data,
     })
 
-def get_user_first_name(username: str) -> str:
-    try:
-        user = User.objects.get(username=username)
-        return user.first_name
-    except User.DoesNotExist:
-        return ""
-
 def get_users_without_stats(
     username_search_string,
     course_key,