Handle transient errors gracefully in health check

[tomach]

Summary of changes

This improves the ping_cratedb_status handler by catching transient errors (like ClientConnectorError and TimeoutError) and logs them as warnings instead of raising unhandled exceptions.

I also had to upgrade black to support match-case syntax.

Checklist

• Link to issue this PR refers to: https://github.com/crate/cloud/issues/2566
• Relevant changes are reflected in CHANGES.rst
• Added or changed code is covered by tests
• Documentation has been updated if necessary
• Changed code does not contain any breaking changes (or this is a major version change)

[plaharanne]

It looks good to me

[widmogrod]

LGTM.

• Checkout the code, test are running on mac
• Code coverage looks good with this functionality

I have a nitpick.

• This PR is shipping two changes - one is "black to support match-case syntax." and second is handling errors gracefully - I would suggest to split them in two PR or two commits. First appraoch allow to have more granular changes and simpler code review, since linter changes are deterministic, and they don't need to block more nuanced changes.

[tomach]

• This PR is shipping two changes - one is "black to support match-case syntax." and second is handling errors gracefully - I would suggest to split them in two PR or two commits. First appraoch allow to have more granular changes and simpler code review, since linter changes are deterministic, and they don't need to block more nuanced changes.

I created #735 for the upgrade of black