Fix linter errors, fix missing import

servicelayer/metrics.py

@@ -1,5 +1,4 @@
 from prometheus_client import (
-    start_http_server,
     Counter,
     Histogram,
     REGISTRY,

servicelayer/taskqueue.py

@@ -15,6 +15,7 @@
 from timeit import default_timer
 
 import pika.spec
+from prometheus_client import start_http_server
 
 from structlog.contextvars import clear_contextvars, bind_contextvars
 import pika

servicelayer/worker.py

@@ -6,6 +6,8 @@
 from banal import ensure_list
 from abc import ABC, abstractmethod
 
+from prometheus_client import start_http_server
+
 from servicelayer import settings
 from servicelayer.jobs import Stage
 from servicelayer.cache import get_redis