Micro-optim in FormController::approveRowChange

TODO says:
"in case of binary fields, this "getString" below is extremely expensive"

In this case, swap the terms of the if to hope to gain a little.

Change-Id: I4ef7b3bf5a9cbe49f7d56462d02ab274cbfd0025
Reviewed-on: https://gerrit.libreoffice.org/60509
Tested-by: Jenkins
Reviewed-by: Lionel Elie Mamane <lionel@mamane.lu>

svx/source/form/formcontroller.cxx

@@ -3737,7 +3737,7 @@ sal_Bool SAL_CALL FormController::approveRowChange(const RowChangeEvent& _rEvent
             }
 
             // TODO: in case of binary fields, this "getString" below is extremely expensive
-            if ( !rColInfo.xColumn->getString().isEmpty() || !rColInfo.xColumn->wasNull() )
+            if ( !rColInfo.xColumn->wasNull() || !rColInfo.xColumn->getString().isEmpty() )
                 continue;
 
             OUString sMessage( SvxResId( RID_ERR_FIELDREQUIRED ) );