Update how-to-configure-network-isolation-with-v2.md

I added a description that changing the v1_legacy_mode parameter from __true__ to __false__ would take time to be reflected.
The taken time was based on my trials (about 30min, 40min, and 60min) and IcM 312245323 (https://portal.microsofticm.com/imp/v3/incidents/details/312245323/home).

Author: shohei1029

articles/machine-learning/how-to-configure-network-isolation-with-v2.md

@@ -111,9 +111,12 @@ The return value of the `az ml workspace update` command may not show the update
 az ml workspace show -g <myresourcegroup> -w <myworkspace> --query v1LegacyMode
 ```
 
+> [!IMPORTANT]
+> Note that it takes about 30 minutes to an hour or more for changing v1_legacy_mode parameter from __true__ to __false__ to be reflected in the workspace. Therefore, if you set the parameter to __false__ but receive an error that the parameter is __true__ in a subsequent operation, please try after a few more minutes.
+
 ---
 
 ## Next steps
 
 * [Use a private endpoint with Azure Machine Learning workspace](how-to-configure-private-link.md).
-* [Create private link for managing Azure resources](../azure-resource-manager/management/create-private-link-access-portal.md).
+* [Create private link for managing Azure resources](../azure-resource-manager/management/create-private-link-access-portal.md).