tdf#125384 allow setting initial tabpage before dialog is running

Change-Id: I79ad38e05e6b66089a0ed47d4054d416b8c61ff8
Reviewed-on: https://gerrit.libreoffice.org/72633
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sfx2/source/dialog/tabdlg.cxx

@@ -1535,9 +1535,8 @@ IMPL_LINK(SfxTabDialogController, DeactivatePageHdl, const OString&, rPage, bool
     }
 
     VclPtr<SfxTabPage> pPage = pDataObject->pTabPage;
-    DBG_ASSERT( pPage, "no active Page" );
     if (!pPage)
-        return false;
+        return true;
 
     DeactivateRC nRet = DeactivateRC::LeavePage;