support custom tts streaming vendor (#377)

lib/utils/speech-utils.js

@@ -624,6 +624,7 @@ function decryptCredential(obj, credential, logger, isObscureKey = true) {
     obj.auth_token = isObscureKey ? obscureKey(o.auth_token) : o.auth_token;
     obj.custom_stt_url = o.custom_stt_url;
     obj.custom_tts_url = o.custom_tts_url;
+    obj.custom_tts_streaming_url = o.custom_tts_streaming_url;
   } else if ('assemblyai' === obj.vendor) {
     const o = JSON.parse(decrypt(credential));
     obj.api_key = isObscureKey ? obscureKey(o.api_key) : o.api_key;