fix(ci): dedupe _public_limiter/_auth_limiter declarations in rate_limit.py (CAR-1330 dev lint fix)

mypy no-redef: the second forward-decl block at line 124 was a duplicate
of the block at line 111. Pre-existing dev branch issue blocking CAR-1356.
Mirrors CAR-1340 uat fix (2b20946).

src/cartsnitch_api/middleware/rate_limit.py

@@ -121,10 +121,6 @@ if settings.rate_limit_redis_enabled:
         logger.warning("Failed to connect to Redis for rate limiting, using in-memory: %s", e)
         _use_redis = False
 
-_public_limiter: RateLimitBackend
-_auth_limiter: RateLimitBackend
-_auth_strict_limiter: RateLimitBackend
-
 if _use_redis and _redis_client:
     _public_limiter = RedisSlidingWindow(
         _redis_client, settings.rate_limit_requests, settings.rate_limit_window_seconds