feat(external-api) support assumed bandwidth bps command + ljm update (#13275)

modules/API/constants.js

@@ -15,3 +15,10 @@ export const API_ID = parseURLParams(window.location).jitsi_meet_external_api_id
  * The payload name for the datachannel/endpoint text message event.
  */
 export const ENDPOINT_TEXT_MESSAGE_NAME = 'endpoint-text-message';
+
+/**
+ * The min value that can be set for the assumed bandwidth.
+ * Setting it to this value means not assuming any bandwidth,
+ * but rather allowing the estimations to take place.
+ */
+export const ASSUMED_BANDWIDTH_BPS = -1;