Removed inheritance of TaskSpecifier, TaskPlanner and CriticAgent from ChatAgent

[Obs01ete]

Description

Removed inheritance of TaskSpecifier, TaskPlanner and CriticAgent from ChatAgent. Now we have 0 mypy errors in camel and test.

Motivation and Context

TaskSpecifier, TaskPlanner and CriticAgent do not follow the signature of step() of ChatAgent. They must be dis-inherited from ChatAgent and a ChatAgent instance used as a member.

Issue #163

This is a list of rules of overriding for python: https://rules.sonarsource.com/python/RSPEC-2638/

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)

Checklist

Go over all the following points, and put an x in all the boxes that apply. If you are unsure about any of these, don't hesitate to ask. We are here to help!

• [x] I have read the CONTRIBUTION guide. (required)
• [ ] My change requires a change to the documentation.
• [x] I have updated the tests accordingly. (required for a bug fix or a new feature)
• [ ] I have updated the documentation accordingly.