Plugin: remove deprecated versions of protocol RPCs

What

The time to put the legacy attestation name endorsement to sleep has come. This MR is the second of a set that target to remove the support for this old name.

This MR removes deprecated versions of protocls RPCs that supported the legacy attestation name endorsement.

This MR is on top of !13449 (merged)

Why

How

Remove occurrences of ..._encoding_with_legacy_attestation_name in the plugin RPC code base.

Manually testing the MR

Check that their are no more ..encoding_with_legacy_attestation_name occurrences in the plugin.

Check that version 0 of run_operation and validate_operation are not available anymore by running a sandboxed node and client.

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