{Storage} az storage account migration start: Add upcoming breaking change warning for confirmation (#31079)

* add breaking change warning for upcoming addition for confirmation during account redundancy change

* use version instead of set date

Author: calvinhzy

src/azure-cli/azure/cli/command_modules/storage/_breaking_change.py

@@ -0,0 +1,19 @@
+# --------------------------------------------------------------------------------------------
+# 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_other_breaking_change
+
+register_other_breaking_change('storage account migration start',
+                               message='Starting from version 2.73.0, changing redundancy configuration would require '
+                                       'additional (y/n) confirmation: "After your request to convert the account’s '
+                                       'redundancy configuration is validated, the conversion will typically complete '
+                                       'in a few days, but can take several weeks depending on current resource '
+                                       'demands in the region, account size, and other factors. '
+                                       'The conversion can’t be stopped after being initiated, and for accounts with '
+                                       'geo redundancy a failover can’t be initiated while conversion is in progress. '
+                                       'The data within the storage account will continue to be accessible with no '
+                                       'loss of durability or availability. '
+                                       'Confirm redundancy configuration change: (y/n)"',
+                               target_version='2.73.0')