style: remove unused List import from llm_model_configs.py

Remove unused typing.List import flagged by ruff F401.

Co-Authored-By: Yue Guobin <yueguobin@outlook.com>

gns3server/schemas/controller/llm_model_configs.py

@@ -14,7 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from typing import Optional, List, Literal
+from typing import Optional, Literal
 from pydantic import BaseModel, Field, ConfigDict
 from uuid import UUID