interpreter: speak into floor

Preconditions:

1. interpreter interprets into the corresponding audio channel
2. There is a "speak-into-floor" button, which is only available for interpreters. The button is "greyed out" / visible but not usable, if the Floor is selected as the current spoken language.
3. interpreter wants to interrupt the session, for example because the interpreter didn't understand and wants the speaker to repeat, or the interpreter wants the speaker to explain an abbreviation.

as an interpreter

1. I continuously press the button.
2. While I'm pressing the button, everything I say does not go into the interpretation audio channel. Instead, it's directed into floor.
3. When I stop pressing the button, everything I say (again) goes into the interpretation audio channel.
4. While the button is pressed, that is strongly visible, for example the button becomes red.

Postconditions:

1. After finishing to press the button, everything I say goes into the interpretation audio channel.