Summary
- Include KMS error in libmongocrypt status.
Background & Motivation
KMS message reports errors with the `kms_request_get_error` function.
C# tests got this error `failed to create KMS message` with no additional information.
KMS message reports errors with the `kms_request_get_error` function.
C# tests got this error `failed to create KMS message` with no additional information.