Transition sidebar: Apply the transition duration right away.

In the desktop version, the value that is entered there always ends up
applied.  In the Online, there was a scenario when it did not: enter a
value and switch slide by clicking the slide sorter.

There is no harm to apply the value right away when the user edits,
because in the desktop version, there was no way to avoid applying the
value anyway.

Change-Id: I519423d60f682735aeb1d471b3397ff9671c15fd
Reviewed-on: https://gerrit.libreoffice.org/72923Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Michael Meeks <michael.meeks@collabora.com>

sd/source/ui/animations/SlideTransitionPane.cxx

@@ -1125,6 +1125,8 @@ IMPL_LINK_NOARG(SlideTransitionPane, DurationModifiedHdl, Edit&, void)
         mpCBX_duration->SetValue(0);
     else
         mpCBX_duration->SetValue(duration_value);
+
+    applyToSelectedPages();
 }
 
 IMPL_LINK_NOARG(SlideTransitionPane, DurationLoseFocusHdl, Control&, void)