Unable to set an endpoint ID when using SpeechTranslationConfig

[jkgh2018]

The speechTranslationConfig is setting the EndpointID to the Endpoint property.
This results in an incorrect URL being constructed and a status code of 500.

cognitive-services-speech-sdk-js/src/sdk/SpeechTranslationConfig.ts
public set endpointId(value: string) {
this.privSpeechProperties.setProperty(PropertyId.SpeechServiceConnection_Endpoint, value);
}

privErrorDetails: "Unable to contact server. StatusCode: 500, Reason: SyntaxError: Failed to construct 'WebSocket':

[rhurey]

PR #139 will have the fix.