`--bootstrap-artifact-source Cache` is required when updating ACR for AKS network isolated cluster

### Describe the bug

When updating your ACR ID using "az aks update" for the feature network isolated cluster, both `--bootstrap-artifact-source Cache` and `--bootstrap-container-registry-resource-id ` need to be specified.
If `--bootstrap-artifact-source Cache` is not specified, the request will be ignored and the ACR ID won't be updated to the cluster.

Ref: https://learn.microsoft.com/en-us/azure/aks/network-isolated?pivots=byo-acr#update-your-acr-id

### Related command

az aks update --resource-group ${RESOURCE_GROUP} --name ${AKS_NAME} --bootstrap-artifact-source Cache --bootstrap-container-registry-resource-id

### Errors

No error raised. The request of updating ACR is ignored.

### Issue script & Debug output

N/A

### Expected behavior

Specify both `--bootstrap-artifact-source Cache` and `--bootstrap-container-registry-resource-id `

### Environment Summary

$ az --version
azure-cli 2.71.0

core 2.71.0
telemetry 1.1.0

Extensions:
azure-firewall 1.2.2
kusto 0.5.0
quota 1.0.0
virtual-wan 1.0.1

Dependencies:
msal 1.31.2b1
azure-mgmt-resource 23.1.1

Python location '/opt/az/bin/python3'
Config directory '/home/binxi/.azure'
Extensions directory '/home/binxi/.azure/cliextensions'

Python (Linux) 3.12.8 (main, Mar 25 2025, 10:55:59) [GCC 9.4.0]

Legal docs and information: aka.ms/AzureCliLegal

Your CLI is up-to-date.

### Additional context

_No response_