Add system note when an issue is unlinked or linked to a violation

What does this MR do and why?

Add system note when an issue is unlinked or linked to a violation.

References

Closes #554254 (closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Ensure you have ultimate license
2. Enable feature flags compliance_violations_report and enable_project_compliance_violations.
3. Visit the compliance violations dashboard. Eg: https://gdk.test:3000/flightjs/blank-project/-/security/compliance_dashboard/violations
4. Open any violation and note its ID.
5. Run the following mutations to link an issue to the above compliance violation

mutation linkViolationIssue {
  linkProjectComplianceViolationIssue(input: {
    violationId: "gid://gitlab/ComplianceManagement::Projects::ComplianceViolation/17",
    projectPath: "flightjs/blank-project",
    issueIid: "11"
  }
  ) {
    violation {
      id
      status
      issues {
        nodes {
          id
          title
        }
      }
    }
    errors
  }
}

6. You can run the above with issues from different projects as well.
7. Run the following mutation to unlink issues

mutation unlinkViolationIssue {
  unlinkProjectComplianceViolationIssue(input: {
    violationId: "gid://gitlab/ComplianceManagement::Projects::ComplianceViolation/17",
    projectPath: "flightjs/blank-project",
    issueIid: "1"
  }) {
    violation {
      id
      status
      issues {
        nodes {
          id
          title
        }
      }
    }
    errors
  }
}

8. Visit the details page of the violation and you should see the linked and unlinked notes in the activity section similar to the screenshot above. Eg: https://gdk.test:3000/flightjs/blank-project/-/security/compliance_violations/17

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