Docs should recommend hidden=true saved objects

[exalate-issue-sync]

While there is a lot of design work left before we can create a thorough BWCA “migration guide”, one thing that we’re sure about is that all saved objects will have to become hidden: true. All of our documentation and examples show exactly the opposite. We also have teams with existing public APIs who are still using {{hidden: false}} saved objects (e.g. data views and security solution) but we don’t have any documentation for them to use a reference

As a starting point we can update our documentation and examples to highlight the purpose of the hidden option and to have enough reference material so they know how to migrate away from that. (For instance highlighting that they need to construct a new SO client with the hidden type enabled to be able to use it)

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)

[TinaHeiligers]

The alternative to changing a saved object type to hidden:true will be only 'hiding' the type from the public HTTP APIs by declaring hiddenFromHttpApis: true. The latter option will allow type owners to use their own domain-specific HTTP APIs without having to use a custom client.

[rudolf]

This was fixed in #144647 let's create a new issue to update our docs to recommend hiddenFromHttpApis: true