Creates an instance of ToggleBrailleCommand.
The application context.
The braille view model.
Announces the unsupported warning.
Plays the warning tone.
Toggles the braille display when a trace is active. Above the trace level
(e.g. the multi-panel figure lobby) there is no data series to render as
braille, so instead of silently ignoring the key it announces a warning and
plays a warning tone — mirroring how l t warns when text mode is off.
Command to toggle the braille display on or off.