In #8602, we started passing a child of the TerminalSettings to the control upon tab initialization, we need to make sure that we are doing this for every call of initializing a new TermControl (we initially forgot to do this for controls initialized during pane split, which led to #9280).

EDIT: Ideally, we do this by having a helper that handles the creation of new TermControls, see DHowett's comment below.