Audit Log settings.update has no information

### Epic

_No response_

### Description

**As a:** user

**I want to:** know what settings where updated when the audit log records a settings.update event

**So that:** I can identify changes and if required revert them

We need to consider what is logged here to avoid anything sensitive being logged, as a starting point we should log which setting was changed but not the value.

This may need some additional work to identify the delta in the settings as the node-red audit log just sends a settings.update event.
Slack thread https://flowforgeworkspace.slack.com/archives/C032Q63FGG1/p1665396141083899

### Which customers would this be availble to

All Users, (CE)

### Acceptance Criteria

- [ ] Appropriate metadata is recorded with the settings.update event

Start by tracing where the settings.update audit event is emitted and review the linked Slack discussion for existing context. Define which changed-setting metadata can be recorded without values or sensitive data, then verify the event includes that metadata and satisfies the acceptance criterion.

Written by the indexing model from the issue text.