Tezt/Dal_node: remove Client dependency in dal_node.ml

What

This MR removes the dependency of client.ml from dal_node.ml.

Why

The main goal is to to extend the Client.t type of Tezt client.ml with a dal_node: Dal_node.t field.

The dal_node not being included in Client.t requires passing it through all the functions because it is needed for the Client.bake_for function. The following commit is an example of such propagation:

!14049 (7379cc4e)

In this example, the only goal of having the dal_node in the arguments of the functions is to provide it to the bake_for function.

How

In order to remove the depency, it is enough to replace Client.endpoint with Endpoint.t in the l1_node_endpoint field of the Dal_node.t type.

Manually testing the MR

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR