OpenAI deployments return rateLimits property that wasn't part of the request

[maciej-skorupka]

Describe the bug When creating an OpenAI deployment (Microsoft.CognitiveServices/accounts/deployments@2023-05-01), there's no option to set rateLimits property. But when running what-if with bicep file, the Modify change is found on rateLimits parameter and deployment is changed.

To Reproduce Steps to reproduce the behavior:

1. Create a bicep file:

resource openaiResource 'Microsoft.CognitiveServices/accounts@2023-05-01' existing = {
  name: 'mygpt'
}

resource openaiDeployment 'Microsoft.CognitiveServices/accounts/deployments@2023-05-01' = {
  name: 'myDeployment'
  sku: {
    capacity: 1
    name: 'Standard'
  }
  parent: openaiResource
  properties: {
    model: {
      format: 'OpenAI'
      name: 'gpt-35-turbo-16k'
      version: '0613'
    }
    raiPolicyName: 'Microsoft.Default'
    versionUpgradeOption: 'OnceCurrentVersionExpired'
  }
}

2. Run az group create on that file.

az deployment group create --resource-group myresourcegroup \
                           --mode Incremental \
                           --template-file deploy.bicep

3. Run az group what-if using that file.

az deployment group what-if --resource-group myresourcegroup \                                        
                            --mode Incremental \
                            --template-file deploy.bicep

4. Observe that output shows Delete should happen on rateLimits.

Note: The result may contain false positive predictions (noise).
You can help us improve the accuracy of the result by opening an issue here: https://aka.ms/WhatIfIssues

Resource and property changes are indicated with these symbols:
  - Delete
  ~ Modify
  * Ignore

The deployment will update the following scope:

Scope: /subscriptions/XXXXXX/resourceGroups/myresourcegroup

  ~ Microsoft.CognitiveServices/accounts/mygpt/deployments/myDeployment [2023-05-01]
    - properties.rateLimits: [
        0:

          count:         1
          key:           "request"
          renewalPeriod: 10

        1:

          count:         1000
          key:           "token"
          renewalPeriod: 60

      ]

  * Microsoft.CognitiveServices/accounts/mygpt

Resource changes: 1 to modify, 1 to ignore.

Expected behavior rateLimits shouldn't be interpreted as a change as it's not set by the request and shouldn't result in a change in az group create