Fix ComposableLifecycleNode autostart not using resolved name

[SuperJappie08]

Description

Introduce fully_qualified_node_name property to ComposableNode and Node, so the property meaning discrepency of node_name can be avoided.
(node_name on Node is the fully qualified node name, while node_name for a ComposableNode was the plain node_name as needed for composition_interfaces/srv/LoadNode)

Fixes #479

Is this user-facing behavior change?

Did you use Generative AI?

No.

Additional Information

ComposableNode looks like it could use a refactor, which could make launch_ros.actions.get_composable_node_load_request a method of the class.
Furthermore, I'm unsure of the need for the property redefinitions of ComposableLifecycleNode (such as node_name etc.).
Since they are inherited as well.

[SuperJappie08]

There are no tests for this, as there is a lack of composable lifecycle demo/example nodes to test with at the moment.