Raise worker version to 173 (also server side)

Move some comments to have a nice output from `isort`.

```
black --exclude='env|packages' .
isort --profile black --skip env --skip venv --skip worker/packages .
```

server/fishtest/api.py

@@ -27,7 +27,7 @@
 on how frequently the main instance flushes its run cache.
 """
 
-WORKER_VERSION = 172
+WORKER_VERSION = 173
 
 flag_cache = {}
 

worker/worker.py

@@ -23,20 +23,17 @@
 from contextlib import ExitStack
 from functools import partial
 
+# Try to import the system wide package (eg requests).
+# Fall back to the local one if the global one does not exist.
 
 packages_dir = os.path.join(os.path.dirname(os.path.realpath(__file__)), "packages")
 sys.path.append(packages_dir)
 
-# Try to import the system wide requests package.
-# Fall back to the local one if the global one does not exist.
-
-import requests
-
 # Several packages are called "expression".
 # So we make sure to use the locally installed one.
 
 import packages.expression as expression
-
+import requests
 from games import (
     FatalException,
     RunException,
@@ -49,7 +46,7 @@
 )
 from updater import update
 
-WORKER_VERSION = 172
+WORKER_VERSION = 173
 HTTP_TIMEOUT = 30.0
 INITIAL_RETRY_TIME = 15.0
 THREAD_JOIN_TIMEOUT = 15.0