Add API spec type to the summary view of a release plan

Because the process is so different between OpenAPI and TypeSpec specs, having this property in the summary of the SDK will help to provide context quickly, instead of the flow we have today where the user needs to:
1. click on the milestone tab
2. Click on either the API readiness milestone and in the app go to the `Associate link PR` so the user can click on the API spec PR and see the type of API spec
3. Click on SDK readiness and in the app look at the steps, if the step `Release summary` is present then it is a TypeSpec flow
4. Another option is to look at the Release plan DevOps work item and from there look at the API child work item and read the property directly