Bin_client: enable agnostic-baker alias in sandbox

This MR aims to bring the support of the octez-agnostic-baker in sandbox mode.

It is build on to of !17694 (merged) as it requires the script to be updated. Indeed, the agnostic baker matches -E or --endpoint but the client's script was using -endpoint. I've fixed the script as -endpoint sounds misleading.

What

Why

How

Manually testing the MR

Run the agnostic baker in sandbox with octez-agnostic-baker run with local node /tmp/lapin --without-dal

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