Add cards test app

[heyitsaamir]

• Tests the cards package out. Found some bugs in serialization
• Adds a cards test
• Made sure these things work from the snippets that are in the docs

PR Dependency Tree

• PR Add cards test app #150 👈
  • PR Add more comprehensive AI tests #151

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[Copilot]

Pull Request Overview

This PR adds a new cards test application to validate the adaptive cards functionality within the Microsoft Teams AI Library. The test demonstrates basic message handling using the Teams Apps framework and validates card serialization features that were found to have bugs during development.

• Adds a complete cards test application with proper project structure
• Updates logging level for graph token failures from warning to debug
• Includes a template manifest file for test applications

Reviewed Changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/cards/src/main.py	Creates main test application with message handling to validate cards functionality
tests/cards/pyproject.toml	Project configuration for the cards test with required dependencies
tests/cards/README.md	Documentation template for the cards test application
templates/test/{{cookiecutter.test_app_name}}/appPackage/manifest.json	Teams app manifest template for test applications
packages/apps/src/microsoft/teams/apps/app.py	Changes graph token failure logging from warning to debug level