Since commit a1d650ce27, window title changes are listened for in the
ShellWindowTracker in order to emit ::tracked-windows-changed when
there are window title changes.
The rest of the things that happen in between (removing the window
from a ShellApp, possibly have it destroyed, and possibly creating a
new ShellApp to re-insert the window) are superfluous and even result
in the altTab switcher popup ending up confused about the applications
available.
Only emit the signal so changes can be followed on D-Bus, but avoid
the ShellApp fiddling otherwise.
Fixes: a1d650ce27 - window-tracker: Emit 'tracked-windows-changed' on title changes
Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/6385
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2634>