Do not select all entities when omitting entity ID in service call

[balloob]

Breaking Change:

It is no longer possible to target all entities by not passing both entity_id and area_id to your service data. This feature was previously deprecated and has been printing warnings. The correct way to target all entities is to set entity_id: all

Description:

Remove the feature to automatically target all entities if you did not specify an entity.

Previously attempted in #25715.

entity_id has not been set to required because it is allowed to just specify area_id to select entities.

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[amelchio]

entity_id has not been set to required because it is allowed to just specify area_id to select entities.

So we now fail silently?

It would be quite useful to have the constraint (need one or the other) encoded in the schemas.

[amelchio]

This comments says that further changes are needed if it is deleted :)

[pvizeli]

We should remove the auto target and convert the warning into error and fail on this service call

[balloob]

I've updated the code to always require either entity_id or area_id. I did some clean up in the process. The change was made by making sure that ENTITY_SERVICE_SCHEMA has been removed and replaced with a function that will extend the passed in schema, but also enforced either key is passed in.