[What's New Analysis] Add missing Azure 13.1 features to existing docs

Summary

Several Azure features from Aspire 13.1 are documented in what's-new but NOT in their respective integration docs.

Missing Features

1. WithDeploymentSlot for App Service (13.1)

What's New says:

builder.AddAzureAppServiceEnvironment("appservice")
    .WithDeploymentSlot("staging");

Current doc: azure-app-service-integration exists but does NOT mention WithDeploymentSlot.

Action: Add deployment slots section to azure-app-service-integration.

2. ClearDefaultRoleAssignments (13.1)

What's New says:

// Disable automatic role assignments on Azure resources
builder.AddAzureStorage("storage")
    .ClearDefaultRoleAssignments();

Current doc: manage-azure-role-assignments covers WithRoleAssignments to override, but NOT ClearDefaultRoleAssignments to completely disable.

Action: Add section on clearing/disabling default roles to manage-azure-role-assignments.

3. Azure Managed Redis Rename (13.1)

Breaking change:

// Old (deprecated)
builder.AddAzureRedisEnterprise("cache");

// New
builder.AddAzureManagedRedis("cache");

Action: Verify azure-cache-for-redis-integration uses new API name.