Audit number of required approvals changes at project level

What does this MR do?

This MR will ensure audit event is recorded both in DB and log file when user successfully update no. of required approvals at Project level. We would like to capture changes to ApprovalProjectRule model and surface it under Project audit events page. The audit event will be recorded for update issued via both App and API.

Extracted from !25583 (closed) to reduce scope.

Parent issue #7531 (closed)

Screenshots

Project-level

(Project > Settings > Audit Events)

Instance-level

(Admin Area > Monitoring > Audit Log)

How the event attributes are mapped to the Audit Events view

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