tdf#114788: fix crash in form-based filter

regression from https://cgit.freedesktop.org/libreoffice/core/diff/svx/source/form/filtnav.cxx?id=85f93697defd9a812a0cda0bc4e9364e28c0339e

Change-Id: If6f248b460a55aa1e30902d5edeb807dabb37d7b
Reviewed-on: https://gerrit.libreoffice.org/47338Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Lionel Elie Mamane <lionel@mamane.lu>

svx/source/form/filtnav.cxx

@@ -1144,7 +1144,7 @@ bool FmFilterNavigator::EditingEntry( SvTreeListEntry* pEntry, Selection& rSelec
     if (!SvTreeListBox::EditingEntry( pEntry, rSelection ))
         return false;
 
-    return pEntry && dynamic_cast<const FmFilterItem*>(static_cast<FmFilterData*>(pEntry->GetUserData())) == nullptr;
+    return pEntry && dynamic_cast<const FmFilterItem*>(static_cast<FmFilterData*>(pEntry->GetUserData())) != nullptr;
 }