AddAzureOpenAI and AddFoundry should support private endpoints

[eerhardt]

aspire/src/Aspire.Hosting.Foundry/FoundryResource.cs

Lines 16 to 17 in d4a9817

	public class FoundryResource(string name, Action<AzureResourceInfrastructure> configureInfrastructure) :
	AzureProvisioningResource(name, configureInfrastructure), IResourceWithEndpoints, IResourceWithConnectionString

aspire/src/Aspire.Hosting.Azure.CognitiveServices/AzureOpenAIResource.cs

Lines 14 to 16 in d4a9817

	public class AzureOpenAIResource(string name, Action<AzureResourceInfrastructure> configureInfrastructure)
	: AzureProvisioningResource(name, configureInfrastructure),
	IResourceWithConnectionString

These 2 resources should support IAzurePrivateEndpointTarget