static getFrameId(evt) {
    return evt.args?.data?.frame ||
      evt.args.data?.frameID ||
      evt.args.frame;
  }
The associated frame ID is set in different locations for different trace events.
This function checks all known locations for the frame ID and returns `undefined` if it's not found.

@param {LH.TraceEvent} evt
@return {string|undefined}