GetResourceOauth2Token returns ValidationException: Error parsing ClientCredentials response

When calling the following CLI command:
```
aws bedrock-agentcore get-resource-oauth2-token --workload-identity-token --resource-credential-provider-name 'tradeforge-m2m' --scopes "email" --oauth2-flow 'M2M'
```

I receive `An error occurred (ValidationException) when calling the GetResourceOauth2Token operation: Error parsing ClientCredentials response`

I have absolutely no way to debug this. The same happens during runtime when using the SDK and there is no way to get to the actual reason as for why this is happening (what exactly was returned by the identity provider).

I'd greatly appreciate some degree of insight into the responses so that I could debug if the issue is on my side or not.