[#1631][BotFrameworkAdapter] process_activity returns HTTP 412 error when exchanging a token

[ceciliaavila]

Fixes #1631

Description

This PR fixes the issue found when exchanging a token from the Host to the Skill. The response status is 412 and the body's description The bot is unable to exchange token. Proceed with regular login.
The fix evaluates the correct exchange_async method response and returns the actual TokenResponse instance.
There is also a fix for the InvokeResponse result in the process_activity method, which now will be returning the body serialized.
Also, two new unit tests were included to address these fixes.

Specific Changes

• bot_framework_adapter.py
  • Imported TokenResponse from botframework.connector.token_api.models as ConnectorTokenResponse named class due to existing TokenResponse from bot.builder.schema.
  • Replaced invoke_response.value in process_activity_with_identity with a new instance with the body serialized.
  • Replaced the condition after the exchange_async token is executed in the exchange_token_from_credentials method for evaluating with the ConnectorTokenResponse and returning the TokenResponse instance.
• test_bot_framework_adapter.py
  • Added the mock _create_token_api_client method in the AdapterUnderTest class to mock the exchange_async method.
  • Added the test test_process_activity_with_identity_token_exchange_invoke_response that will evaluate that the InvokeResponse comes serialized.
  • Added the test test_exchange_token_from_credentials that will evaluate that returns the TokenResponse correctly.

Testing

[axelsrz]

@ceciliaavila this looks great! could you update the branch to merge it?

[ceciliaavila]

@ceciliaavila this looks great! could you update the branch to merge it?

Done @axelsrz! Thanks.