[Core deprecations service] Require manual corrective steps for config deprecations

[alisonelizabeth]

The new deprecations service provided by core (#94845) currently doesn't require config deprecations to provide manual corrective steps. This leads to a poor UX, as a user doesn't have context on how to resolve a deprecation. It also is an inconsistent experience as some config deprecations provide manual corrective steps, while others do not.

This issue is to enforce all config deprecations to register manual corrective steps and throw an error if none are provided.

Note: The existing config deprecations will need to be updated before this can be enforced.

[elasticmachine]

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

[joshdover]

The first step to this should be auditing all existing deprecations and creating a checklist for teams to address this. #83910 is a good example of how we can coordinate this.

[pgayvallet]

Note that all config deprecations relying on the provided rename and unused factories are declaring manual corrective steps, as these factories are defining them. So only the 'custom' config deprecations are concerned here.