GUI: Scripting buffer display only shows the active console

As a user I would like the scripting buffer display created in https://github.com/ISISComputingGroup/ibex_gui/pull/917 to work correctly for multiple unique consoles. It does not as it shows the following behaviour:

* Create two unique consoles side-by-side
* Print in a tight loop in one console
* Press the buffer full button in the other
* The console with the tight loop is cleared, as a user I would expect the button I press to affect the console that it is tied to

Inizia esaminando la visualizzazione del buffer di scripting introdotta in pull request 917 e riproduci il problema con due console distinte affiancate. Stampa continuamente in una console, premi il pulsante di buffer pieno nell’altra e verifica che venga svuotata solo la console associata al pulsante.

Scritto dal modello di indicizzazione a partire dal testo della issue.