Use IP address from request on audit events

What does this MR do?

Use IP address coming from request (via request.remote_ip) if provided, and fall back to user sign-in address. Users can reuse login session and the current_sign_in_ip is not always reflecting the real current IP address.

This is one example of the correct usage.

I will raise another MR to revisit all callers of AuditEventService and make sure we pass in the request.remote_ip.

Relates to #217439 (closed)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team