Add fill attributes to border background item set

...so the new background tab page works correctly in Calc Border/
Background dialog

Change-Id: I4121d5ef0e69ccd6f819b5ea760461004d484364
Reviewed-on: https://gerrit.libreoffice.org/68369
Tested-by: Jenkins
Reviewed-by: Jim Raykowski <raykowj@gmail.com>

svx/source/dialog/hdft.cxx

@@ -582,7 +582,8 @@ IMPL_LINK_NOARG(SvxHFPage, BackgroundHdl, weld::Button&, void)
 
             pBBSet.reset( new SfxItemSet(
                 *GetItemSet().GetPool(),
-                {{nBrush, nBrush},
+                {{XATTR_FILL_FIRST, XATTR_FILL_LAST},
+                {nBrush, nBrush},
                 {nOuter, nOuter},
                 {nInner, nInner},
                 {nShadow, nShadow}}) );