Add kibana.saved_object.name to audit log schema

[legrego]

Relates to #100523.

Our Saved Object audit logs capture the type and id of each saved object, but lack a human-readable component. We need to provide the capability for these audit records to include a friendlier identifier.

Motivation

The response-ops team would like to leverage this name field to enhance the audit logs they are generating. This also takes us one step closer to resolving #100523

Tasks

Beta Give feedback

1. Choose name for this field. Should this be name, title, or something else? Does ECS offer any guidance?
2. Add a saved_object.name property to our [KibanaAudit interface].(https://github.com/elastic/kibana/blob/6bfdde6cfcdb1ec876f0177572bfbe28abb8fd2f/x-pack/packages/security/plugin_types_server/src/audit/audit_events.ts#L26-L29)
3. Ensure audit log consumer (i.e. other plugins) can successfully record audit events with this new property.
4. Update the Kibana Audit Log integration to accept this new property. (https://github.com/elastic/integrations/tree/main/packages/kibana/data_stream/audit)

Out of scope

Explicitly out of scope is the rest of the work to resolve #100523, which includes populating this field for all SO types/operations.

[elasticmachine]

Pinging @elastic/kibana-security (Team:Security)