Microsoft.ContainerRegistry anonymousPullEnabled docs should clarify not avail all SKUs

[devlead]

Unsure if this is the right place, but currently looking at just Bicep/Arm docs it's not clear that anonymousPullEnabled:true isn't always avail.

azure-rest-api-specs/specification/containerregistry/resource-manager/Microsoft.ContainerRegistry/preview/2022-02-01-preview/containerregistry.json

Lines 4855 to 4858 in be6cd9c

	"anonymousPullEnabled": {
	"description": "Enables registry-wide pull from unauthenticated clients.",
	"type": "boolean"
	}

It should be documented that this is SKU-dependent and not available in all tiers.

Anonymous pull access is a preview feature, available in the Standard and Premium service tiers.

Reference: https://learn.microsoft.com/en-us/azure/container-registry/anonymous-pull-access

[RakeshMohanMSFT]

@devlead Thank you for reaching out, we are looking into it.