[release/9.3] Respond to API Review feedback

[eerhardt]

Customer Impact

Adjusting our public APIs before release, so we don't have to make breaking changes, or live with unwanted API shape.

See API review comments on #8736.

Testing

Unit tests.

Risk

Low since these APIs are either experiemental or haven't shipped yet.

Regression?

No

[Copilot]

Pull Request Overview

This PR addresses API review feedback by refining the public API surface and consolidating namespaces while removing unused or redundant references.

• Removed obsolete using directives in test files.
• Added or updated Experimental attributes and suppression pragmas in production code.
• Updated access modifiers and namespaces to streamline the API design.

Reviewed Changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/Aspire.Hosting.Azure.Tests/AzureContainerRegistryTests.cs	Removed unused using directive.
tests/Aspire.Hosting.Azure.Tests/AzureContainerAppsTests.cs	Removed unused using directive.
tests/Aspire.Hosting.Azure.Tests/AzureAppServiceTests.cs	Removed unused using directive.
src/Aspire.Hosting/ResourceBuilderExtensions.cs	Added Experimental attribute for publishing callback.
src/Aspire.Hosting/Publishing/PublishingContext.cs	Added using statement and Experimental attribute.
src/Aspire.Hosting/Publishing/Publisher.cs	Added pragma suppression for Experimental API warning.
src/Aspire.Hosting/PublisherDistributedApplicationBuilderExtensions.cs	Changed API access from public to internal and removed the Experimental attribute.
src/Aspire.Hosting/CompatibilitySuppressions.xml	Updated suppressions for removed experimental publishers.
src/Aspire.Hosting/ApplicationModel/PublishingCallbackAnnotation.cs	Added using statement and Experimental attribute.
src/Aspire.Hosting/ApplicationModel/ContainerRegistryReferenceAnnotation.cs	Added using statement and Experimental attribute.
src/Aspire.Hosting.Kubernetes/KubernetesEnvironmentResource.cs	Added pragma suppression for Experimental API warning.
src/Aspire.Hosting.Docker/DockerComposeEnvironmentResource.cs	Added pragma suppression for Experimental API warning within publish method.
src/Aspire.Hosting.Azure/AzurePublishingContext.cs	Converted a public field to an immutable property.
src/Aspire.Hosting.Azure/AzureEnvironmentResourceExtensions.cs	Updated using directives and namespace declaration.
src/Aspire.Hosting.Azure.Storage/AzureBlobStorageContainerResource.cs	Updated namespace from Aspire.Hosting to Aspire.Hosting.Azure.
src/Aspire.Hosting.Azure.ContainerRegistry/AzureContainerRegistryResource.cs	Normalized pragma format and updated namespace.
src/Aspire.Hosting.Azure.ContainerRegistry/AzureContainerRegistryExtensions.cs	Removed unused using directive.
src/Aspire.Hosting.Azure.AppService/AzureAppServiceEnvironmentResource.cs	Updated namespace from Azure.AppService to Azure.
src/Aspire.Hosting.Azure.AppService/AzureAppServiceEnvironmentExtensions.cs	Introduced pragma suppression around annotation use.
src/Aspire.Hosting.Azure.AppContainers/AzureContainerAppExtensions.cs	Introduced pragma suppression around annotation use.

[davidfowl]

Can you also make the publishing apis experimental (annotation and WithPublishingCallback?)

[eerhardt]

Can you also make the publishing apis experimental (annotation and WithPublishingCallback?)

I am making them experimental:

aspire/src/Aspire.Hosting/Publishing/PublishingContext.cs

Lines 18 to 19 in f092e67

	[Experimental("ASPIREPUBLISHERS001", UrlFormat = "https://aka.ms/aspire/diagnostics/{0}")]
	public sealed class PublishingContext(

aspire/src/Aspire.Hosting/ResourceBuilderExtensions.cs

Lines 294 to 295 in f092e67

	[Experimental("ASPIREPUBLISHERS001", UrlFormat = "https://aka.ms/aspire/diagnostics/{0}")]
	public static IResourceBuilder<T> WithPublishingCallback<T>(this IResourceBuilder<T> builder, Func<PublishingContext, Task> callback) where T : IResource