Updating blueprint commands with deprecation message.

Author: Dante DG

src/blueprint/azext_blueprint/_breaking_change.py

@@ -0,0 +1,18 @@
+# --------------------------------------------------------------------------------------------
+# Copyright (c) Microsoft Corporation. All rights reserved.
+# Licensed under the MIT License. See License.txt in the project root for license information.
+# --------------------------------------------------------------------------------------------
+
+
+from azure.cli.core.breaking_change import register_command_group_deprecate, register_other_breaking_change
+
+
+register_command_group_deprecate('az blueprint')
+
+message = """Blueprints and associated commands will be deprecated
+' as early as July 2026. Customers are encouraged to transition to
+' Template Specs and Deployments Stacks to support their scenarios beyond that date.
+' Migration documentation is available at
+' https://learn.microsoft.com/en-us/azure/azure-resource-manager/bicep/migrate-blueprint."""
+
+register_other_breaking_change('az blueprint', message)

src/blueprint/azext_blueprint/custom.py

@@ -114,8 +114,8 @@ def build_arguments_schema(args_schema):
         arg_group="Resource_scope",
         help="Use subscription for the scope of the blueprint. If --management-group is not specified, "
              "--subscription value or the default subscription will be used as the scope.")
-    args_schema.resource_scope._required = False
-    args_schema.resource_scope._registered = False
+    args_schema.resource_scope._required = False  # pylint: disable=W0212
+    args_schema.resource_scope._registered = False  # pylint: disable=W0212
     return args_schema