feat(Wrapper) Added handling of Cognito logout urls.

[czarny]

See https://docs.aws.amazon.com/cognito/latest/developerguide/logout-endpoint.html

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Changes proposed in this Pull Request:

AWS Cognito service requires client_id and logout_uri parameters in the end session endpoint (https://docs.aws.amazon.com/cognito/latest/developerguide/logout-endpoint.html). Updated the filter function to create correct url if token is issued by the Cognito.