3.0 Deprecation Warning: Remove deprecated Message method

[ancalita]

Background
This warning was found in:

• rasa.shared.nlu.training_data.message.py:L188

"""`get_combined_intent_response_key` is deprecated and ""
""will be removed in Rasa 3.0.0. ""
""Please use `get_full_intent` instead."""

Definition of Done

• resolve warning in 3.0 version
• Removed the method from the codebase.
• Added a changelog entry for 3.0 saying we've removed the previously deprecated method.
• Removed the references in the docs

[samsucik]

Can this be done right now? For 3.0 stuff, do we simply target main?

In any case, since the deprecated method doesn't appear anywhere in our Rasa Open Source tests or docs, the definition of done can be, I think, as simple as:

1. Removed the method from the codebase.
2. Added a changelog entry for 3.0 saying we've removed the previously deprecated method.

[ancalita]

Can this be done right now? For 3.0 stuff, do we simply target main?

I think all deprecations will be part of the prep work that can be done after the 2.8. release, targeting main - @m-vdb correct me if I'm wrong about the timeline?

[m-vdb]

yep 👍🏻