When updating to a new bucket, make sure a device is selected

[fe-wickham]

As an example if you are on frost-projects with the audioblade device selected and switch to a bucket with only audiomini, the audiomini device is unselected at load.

Minimum implementation:

• On selecting Update for an S3 bucket, the first device is always selected.

Optional extended implementation:

• On selecting Update for an S3 bucket, if the current device exists in the new bucket then keep that device selected otherwise select the first device