fix: only try to create storage client if storage is enabled

[pauldambra]

Problem

In this Slack thread @macobo reported that without object storage configured there were frequent unhelpful log messages and requests were delayed by the healthcheck.

The object_storage.py module did not check if storage was enabled before trying to create an s3 client

Changes

• does not try to create an s3 client if object storage is not enabled
• returns False from the health check if object storage is not enabled without checking for bucket access
• aggressively reduces timeout for S3 client so we don't need to wait 5 seconds on a service with very high availability and low latency

Note

• preflight check does not warn someone if object storage is disabled (see feat(object storage): add unused object storage #9846)
• test file placement is to match tests being added in feat: session recording to s3 - posthog only #9901

How did you test this code?

ran it locally and added a test to clarify behaviour

[hazzadous]

LGTM to resolve issues people may be having

I gather now we'd want anywhere that calls this to check if None was returned?

[pauldambra]

Yep, possibly better to have a null object