[BUG] Azure EventHub name validation is inconsistent

Original issue in the Azure Service Operator project: https://github.com/Azure/azure-service-operator/issues/4890

### API Spec link

https://github.com/Azure/azure-rest-api-specs/blob/7c640375cebac863ef3430e8ac9aa8cae4843677/specification/eventhub/resource-manager/common/v1/definitions.json#L154

### API Spec version

2023-01-01

### Describe the bug

The validation is inconsistent
```
"pattern": "^[a-zA-Z][a-zA-Z0-9-]{6,50}[a-zA-Z0-9]$",
"minLength": 6,
"maxLength": 50,
```

pattern and minLength don't match

### Expected behavior

validations should match

### Actual behavior

they don't

### Reproduction Steps

create object with name `abcdef` which is valid according to docs: https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/resource-name-rules#microsofteventhub

### Environment

_No response_

Open the linked definitions.json at line 154 and compare its pattern, minLength, and maxLength with the Microsoft Event Hubs naming rules for the 2023-01-01 spec. Reproduce with the name `abcdef`; done means the schema constraints agree with the documented rules and accept or reject that example consistently.

Written by the indexing model from the issue text.