Revert "Resolves tdf#155167 - Start center app pane issue under gtk3"

This reverts commit b7632b68c5398fce8a22ec09414e0075709fbc32.

Reason for revert: Scrolled window looks ugly and does not solve the issue; we just cannot support +2x scaling on small screens

Change-Id: I1c908dfc801a3867597feefa2a8852b871f7df3f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/151526
Tested-by: Jenkins
Reviewed-by: Heiko Tietze <heiko.tietze@documentfoundation.org>
diff --git a/sfx2/uiconfig/ui/startcenter.ui b/sfx2/uiconfig/ui/startcenter.ui
index 4b4cdac..d8d27b8 100644
--- a/sfx2/uiconfig/ui/startcenter.ui
+++ b/sfx2/uiconfig/ui/startcenter.ui
@@ -106,7 +106,6 @@
              <object class="GtkScrolledWindow" id="scrollapps">
                <property name="visible">True</property>
                <property name="can-focus">True</property>
                <property name="hscrollbar-policy">never</property>
                <property name="shadow-type">in</property>
                <child>
                  <object class="GtkViewport">