Skip unknown properties when mapping EndpointTests

[muhammad-othman]

Description

Skip unknown properties when mapping EndpointTests

Motivation and Context

This PR change allows the .NET SDKs to ignore unknown properties so the endpoints team can make additive changes and add new endpoint properties without requiring support from the .NET SDK.
This way they can ship the endpoint rules updates and SDKs will benefit from the addition whenever they decide to implement the feature instead of having to wait for all SDKs to schedule and complete the work.

Testing

• DRY_RUN-d5c8264f-2be3-4cca-a410-a4aebf9bf916
• Ran the generator using some models that includes unknown endpoint properties.

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have read the README document
• I have added tests to cover my changes
• All new and existing tests passed

License

• I confirm that this pull request can be released under the Apache 2 license