Allow scrolling over tray icon to switch between icons when there are fewer than 4 devices

Created by: p-himik

Information

• Solaar version (solaar --version and git describe --tags): solaar 1.1.1, 1.1.1-135-gd115ade2

Is your feature request related to a problem? Please describe. It would be useful for me to be able to switch between which device the tray icon shows, even though I have only two devices. This commit has introduced such an ability, but for some reason it doesn't enable it for people with fewer than 4 devices. Specifically, this is the block that does the check and where I think 4 should be replaced with 2 (or 3 if the receiver itself is in that list as well, although ideally those should probably be filtered out before the check): https://github.com/pwr-Solaar/Solaar/blob/1ace3ef4f4cc90520d5607fde073e6cd1b66d56a/lib/solaar/ui/tray.py#L87-L90