[LiveComponent] Remove silent dependency on Doctrine

[weaverryan]

To reproduce: in a project where Doctrine is not installed, run:

composer require symfony/ux-live-component:@dev

Result:

The service "ux.live_component.doctrine_entity_property_hydrator" has a dependency
on a non-existent service "doctrine". Did you mean this: "ux.live_component.doctrine_entity_property_hydrator"?

That's true! This service should be optional and not registered if Doctrine is not present.

UPDATE

We have the same problem if serializer is not installed - with the service ux.live_component.serializer_property_hydrator.