tdf#86472 Fix breeze borders and set breeze_dark fallback

Change-Id: Id7c536fee42e9f8c69dd058aa683baf5be58def6
Reviewed-on: https://gerrit.libreoffice.org/29620
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Yousuf Philips <philipz85@hotmail.com>

vcl/source/image/ImplImageTree.cxx

@@ -182,6 +182,8 @@ OUString ImplImageTree::fallbackStyle(const OUString &style)
         return OUString("galaxy");
     else if (style == "sifr")
         return OUString("breeze");
+    else if (style == "breeze_dark")
+        return OUString("breeze");
 
     return OUString("tango");
 }