[Breakdown] AppConfiguration Check * HEAD endpoints

[ahsonkhan]

• Sample building with expected design
• Sample running
• Readme doc
• (optional) Hand-written SDK matches expected design
• Live Tests
• Recorded Tests
• Generated code matches expected design

checkKeys - https://github.com/Azure/azure-rest-api-specs/blob/85ed8fc06e19c902c95b531cbd8a643428d5f28d/specification/appconfiguration/AppConfiguration/routes.tsp#L90

checkKeysValues - https://github.com/Azure/azure-rest-api-specs/blob/85ed8fc06e19c902c95b531cbd8a643428d5f28d/specification/appconfiguration/AppConfiguration/routes.tsp#L199

checkKeyValue - https://github.com/Azure/azure-rest-api-specs/blob/85ed8fc06e19c902c95b531cbd8a643428d5f28d/specification/appconfiguration/AppConfiguration/routes.tsp#L404

checkSnapshots - https://github.com/Azure/azure-rest-api-specs/blob/85ed8fc06e19c902c95b531cbd8a643428d5f28d/specification/appconfiguration/AppConfiguration/routes.tsp#L485

checkSnapshot - https://github.com/Azure/azure-rest-api-specs/blob/85ed8fc06e19c902c95b531cbd8a643428d5f28d/specification/appconfiguration/AppConfiguration/routes.tsp#L629

checkLabels - https://github.com/Azure/azure-rest-api-specs/blob/85ed8fc06e19c902c95b531cbd8a643428d5f28d/specification/appconfiguration/AppConfiguration/routes.tsp#L702

checkRevisions - https://github.com/Azure/azure-rest-api-specs/blob/85ed8fc06e19c902c95b531cbd8a643428d5f28d/specification/appconfiguration/AppConfiguration/routes.tsp#L866

REST API docs:
https://learn.microsoft.com/en-us/rest/api/data-plane/appconfiguration/check-keys/check-keys?view=rest-data-plane-appconfiguration-2023-11-01&tabs=HTTP

GoLang generates these HEAD operations, but they don't seem to be used anywhere, nor expose publicly on the public ConfigurationClient:
https://github.com/Azure/azure-sdk-for-go/blob/0de654744232cf8aaed01dee831bb81ea1f97b02/sdk/data/azappconfig/internal/generated/zz_azureappconfiguration_client.go#L38

[ahsonkhan]

Other language SDKs do not expose CheckX HEAD method operations within the client SDKs.
There's no known scenario atm, and hence C++ will follow suite and leave these out, until we see a customer request for it.