Address feedback on Azure Container Registry

[captainsafia]

Follow-ups to #9059.

This pull request includes updates to improve naming consistency, clarify code behavior, and reorganize files for better project structure. The key changes include renaming properties in the AzureContainerRegistryResource class, updating comments for clarity, and moving the ContainerRegistryReferenceAnnotation file to a more appropriate namespace.

Naming consistency updates:

• Renamed properties in AzureContainerRegistryResource to improve clarity and consistency:
  • RegistryName was renamed to NameOutputReference.
  • RegistryEndpoint was renamed to Endpoint.
  • Updated references to these properties throughout the class. [1] [2]

Code behavior clarification:

• Updated a comment in AzureContainerAppsInfrastructure.cs to clarify that the ComputeEnvironment property will be null when using azd. Removed associated pragma warnings for cleaner code.

File reorganization:

• Moved ContainerRegistryReferenceAnnotation to the Aspire.Hosting.ApplicationModel namespace and updated its file path to better reflect its purpose and usage.