support for or1 instances in Opensearch

### Name of the resource

AWS::OpenSearchService::Domain

### Resource name

_No response_

### Description

or1 instances seem to be not supported:

```
Invalid instance type: or1.2xlarge.search
```

It would be great if these could be added soon

### Other Details

_No response_

The affected resource is AWS::OpenSearchService::Domain, and the reported failure is Invalid instance type for or1.2xlarge.search. Start by reviewing the repository guidance or coverage entry for this resource and how supported instance types are tracked. Done means the or1 instance type is accepted for the resource without that validation error.

Written by the indexing model from the issue text.