[Bug] fix misusing ACCESS_TOKEN_EXPIRE_MINUTES in jwt on exp (#21030)

Co-authored-by: tech <cto@sb>

api/controllers/web/passport.py

         )
         db.session.add(end_user)
         db.session.commit()
-    exp_dt = datetime.now(UTC) + timedelta(hours=dify_config.ACCESS_TOKEN_EXPIRE_MINUTES * 24)
+    exp_dt = datetime.now(UTC) + timedelta(minutes=dify_config.ACCESS_TOKEN_EXPIRE_MINUTES)
     exp = int(exp_dt.timestamp())
     payload = {
         "iss": site.id,