Apply ruff fixes

app/services/ldap.py

@@ -7,7 +7,6 @@ successful profile is provisioned locally on first sign-in.
 """
 
 import logging
-
 from dataclasses import dataclass
 
 from fastapi.concurrency import run_in_threadpool
@@ -43,7 +42,7 @@ def _bind_and_fetch(username: str, password: str) -> LdapIdentity | None:
     )
     try:
         conn = ldap3.Connection(server, user=user_dn, password=password, auto_bind=True)
-    except LDAPException as e:
+    except LDAPException:
         logging.exception("Failed to log into LDAP for user %s", user_dn)
         # Wrong credentials, unreachable server, or a refused bind.
         return None