Workaround failure of the gapi to initialise correctly

When I was testing things previously with the google apis import, I occasionally found that gapi would fail to initialise itself correctly (on load) and then doing things with gapi.auth would fail.

The unit tests are now hitting intermittent failures following the recent changes to SidebarApp#_onWorkerReady. The changes happen after the contacts initialisation and are vital for getting the whole app running, however, with this gapi exception being thrown, the other items aren't being called.

The correct/full fix is probably to stop using gapi, or use something different, but given the amount of work, it seems better to work around the failure for now (whilst logging it), and come back to rework later.