Update Azure.Provisioning API from experimental to stable version

[Copilot]

Updated documentation to use the stable Azure.Provisioning API instead of the experimental version that was used before .NET Aspire 9.0.

Changes Made

• Updated docs/troubleshooting/name-is-already-in-use.md to use the new stable Azure.Provisioning API:
  • Replaced old experimental callback signature (resource, construct, store) => with ConfigureInfrastructure(infra =>
  • Replaced store.AssignProperty(p => p.Name, "'noncalculatedname'"); with direct property assignment appConfigStore.Name = "noncalculatedname";
  • Added proper using statement for Azure.Provisioning.AppConfiguration

Before

var appConfig = builder.AddAzureAppConfiguration(
    "appConfig",
    (resource, construct, store) =>
{
    store.AssignProperty(p => p.Name, "'noncalculatedname'");
});

After

using Azure.Provisioning.AppConfiguration;

var appConfig = builder.AddAzureAppConfiguration("appConfig")
    .ConfigureInfrastructure(infra =>
    {
        var appConfigStore = infra.GetProvisionableResources()
                                  .OfType<AppConfigurationStore>()
                                  .Single();
        
        appConfigStore.Name = "noncalculatedname";
    });

Verification

• ✅ Confirmed no other files contain old Azure.Provisioning experimental patterns
• ✅ Verified all existing snippet files are already using the correct stable API
• ✅ Ensured the updated example follows the same pattern as other Azure.Provisioning examples in the docs

The changes align with the Azure.Provisioning version update that moved from experimental/preview packages to stable versions in .NET Aspire 9.0, as documented in the breaking changes.

Fixes #1652.

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Internal previews

📄 File	🔗 Preview link
docs/troubleshooting/name-is-already-in-use.md	docs/troubleshooting/name-is-already-in-use

Rubbish.