Add tests for DateTimePrompt and NumberPrompt

[ceciliaavila]

Proposed Changes

• Add a new test for DateTimePrompt using Recognizers-Text.DateTime.
  
• Add a new test for NumberPrompt using Recognizers-Text.Number.
  
• Minor fixes on NumberPrompt class to use recognize_number method (replaced ChoiceRecognizer with NumberRecognizer for parity with DotNet implementation).

We ran all tests locally, also, we configured an Azure Pipeline to automatically run the tests.

Note: It's necessary to update the Recognizers-Text-Number package with the fix made in PR# 1554 of Recognizers-Text

Steps to configure a Pipeline for CI:

1. Add a Use Python task. Configure it to use the latest version of python.
   
2. Add a Command Line task to run all the test in the botbuilder-libraries.
   
   The script used is:

pip install -e ./libraries/botbuilder-schema
pip install -e ./libraries/botframework-connector
pip install -e ./libraries/botbuilder-core 
pip install -e ./libraries/botbuilder-azure
pip install -r ./libraries/botframework-connector/tests/requirements.txt
pip install -e ./libraries/botbuilder-ai
pip install -e ./libraries/botbuilder-dialogs
pip install -e ./libraries/botbuilder-applicationinsights

cd libraries
	
pytest --tb=line

In this image we can see the tests ran successfully: