fix: update Microsoft Teams message structure and theme color handling

[SteKoe]

This pull request refactors the Microsoft Teams notifier implementation in the Spring Boot Admin server to use Adaptive Cards instead of the legacy message format, improving compatibility with Microsoft Teams and enhancing message structure and flexibility. It also updates the tests to validate the new message format and color handling.

Migration to Adaptive Card format for Microsoft Teams notifications:

• Refactored the message-building logic in MicrosoftTeamsNotifier to construct Adaptive Card messages, replacing the legacy Section-based format with a new structure using Message, Attachment, AdaptiveCard, and CardElement classes. The new format organizes message content into a card body with title, service name, subtitle, and a fact set, improving Teams compatibility and presentation. [1] [2]
• Changed the color handling in notifications to use Teams' named colors ("Good", "Attention", "Accent") instead of hex codes, updating both the default color expression and all references in code and tests. [1] [2]

Enhancements and code quality improvements:

• Added a helper method addFactIfNotNull to only include non-null facts in the notification payload, ensuring cleaner messages.
• Updated the Fact record to use title instead of name to match the Adaptive Card schema.

Test suite updates:

• Refactored all notifier tests to validate the new Adaptive Card message structure, including JSON structure assertions and new helper methods for extracting and verifying card content and colors. [1] [2] [3] [4] [5] [6] [7] [8] [9]
• Added a comprehensive test to verify that the serialized message matches the expected Adaptive Card JSON structure.

These changes modernize Microsoft Teams integration, improve maintainability, and ensure robust test coverage for the new notification format.

Example

fixes #5321