fix: allow None in transform_year

Author: 1ukastesar

features/verification.py

@@ -185,9 +185,12 @@ async def resend_code(self, login: str, inter: disnake.ApplicationCommandInterac
         await self.gen_code_and_send_mail(inter, user, mail_postfix, True)
 
     @staticmethod
-    def transform_year(raw_year: str):
+    def transform_year(raw_year: str | None):
         """Parses year string originally from /etc/passwd into a role name"""
 
+        if raw_year is None:
+            return None
+
         if raw_year.lower() == "exstudent":
             return "ExStudent"