Revert increased timeout for reporting worker

This reverts commit 603acc8b1e +
This reverts commit edad1c9a21.

The cause of the slowness was fixed in [1] and since [2] we now
have data to prove it: each query to get the data is taking under
5 minutes, so it's safe to lower the timeout again.

[1]: https://github.com/alphagov/notifications-api/pull/3417
[2]: https://github.com/alphagov/notifications-api/pull/3437

app/config.py

@@ -145,7 +145,7 @@ class Config(object):
     SQLALCHEMY_POOL_SIZE = int(os.environ.get('SQLALCHEMY_POOL_SIZE', 5))
     SQLALCHEMY_POOL_TIMEOUT = 30
     SQLALCHEMY_POOL_RECYCLE = 300
-    SQLALCHEMY_STATEMENT_TIMEOUT = int(os.environ.get('SQLALCHEMY_STATEMENT_TIMEOUT', 1200))
+    SQLALCHEMY_STATEMENT_TIMEOUT = 1200
     PAGE_SIZE = 50
     API_PAGE_SIZE = 250
     TEST_MESSAGE_FILENAME = 'Test message'

manifest.yml.j2

@@ -57,7 +57,6 @@
   'notify-delivery-worker-reporting': {
     'additional_env_vars': {
       'CELERYD_PREFETCH_MULTIPLIER': 1,
-      'SQLALCHEMY_STATEMENT_TIMEOUT': 7200
     }
   },
   'notify-delivery-worker-priority': {},