Due to peculiarities in handling of terminal panes (namely the fact that
they are not actually tracked by the Workspace::active_pane member), it
was possible to get into a state where status bar items "lost track" of
an active pane item; one way to reproduce it was to open a new terminal
via "workspace: new terminal" with a pane open in a central view; once a
new terminal is opened, the language selector and line number indicator
lose track of an active item. Focusing central view does nothing - it
will only go away after switching a tab in the central view.

To remedy this, we now always notify the status bar items of a pane
focus change, even if Workspace::active_pane points to the same pane.

Release Notes:

- Fixed status bar focus issues when spawning a terminal via `workspace:
new terminal` action.