Unable to determinate toolbar button status programatically

[brbrr]

For automated tests (and for VoiceOver users) we need to be able to check toolbar status programmatically. For this, we can change expand button label to reflect it's status i.e. formatToolbarButton && formatToolbarButtonExpanded

Also, toolbar expand button don't have an accessibility selector, which makes it hard to locate.

[diegoreymendez]

@brbrr - Changing the "Enhancement" label since the idea of that one is to use it for user-facing changes.