AKS: Nodepool name field needs validation for unsupported format

[cpinjani]

Setup
Rancher version: v2.9-a9534addc5745ec2c93cde7f5e3c54bc9b3a1f91-head
Browser type & version: Chrome latest

Describe the bug
AKS Nodepool name field needs validation for unsupported format. This validation was present on old UI, but missing on new UI.

To Reproduce

• Create downstream AKS cluster
• Provide nodepool name in unsupported format eg. agentPool

Screenshots
2.8:

2.9 allows cluster creation which eventually fails:

[valaparthvi]

Validated on Rancher(v2.9-a9355940c0629ca419b7dd3e4098c4ea0e52c0c0-head); Dashboard(master 46a44c1), it is partially fixed.

• There is validation for unsupported characters.
  

• There is no inline validation for unsupported length, even though the creation fails later on with error:

 Error failed to create cluster: PUT https://management.azure.com/subscriptions/80de5134-ca65-4731-be21-13fb1f0910a2/resourceGroups/pvala-aks-rg/providers/Microsoft.ContainerService/managedClusters/pvala-aks-invalid-np-name -------------------------------------------------------------------------------- RESPONSE 400: 400 Bad Request ERROR CODE: InvalidParameter -------------------------------------------------------------------------------- { "code": "InvalidParameter", "details": null, "message": "The value of parameter agentPoolProfile.name is invalid. Please see https://aka.ms/aks-naming-rules for more details.", "subcode": "", "target": "agentPoolProfile.name" } -------------------------------------------------------------------------------- 

[mantis-toboggan-md]

@valaparthvi I'd like to track adding node pool name length validation with #11405 and keep this ticket for the invalid character issue if that works for you