qterminal: update to 1.4.0

qterminal-1.4.0 / 2023-11-05
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* Handled bell (BEL, '\a') via libcanberra, and added an "Audible bell" option.
* Use `qWarning().noquote()`.
* Ported away from deprecated Qt::MidButton.
* Let the latest QTermWidget library set TERM.
* Corrected tab order in settings dialog.
* Removed an unused non POD variable.
* Supported Putty-style mouse button swap.
* Avoided a case of null pointer dereference.

(gutteridge)