Issue description:

The Pattern Grid contains no option to overwrite patterns when supplied with a written one that is supposed to be overwritten.

To reproduce, open a Pattern Grid, put in a written Pattern in the bottom slot and keep the top slot empty.

What happens:

The "write" button is disabled without any blank patterns inside.

What is expected to happen:

As long as theres a written pattern to overwrite, the "write" button should enable aswell.

Version:

• Minecraft: 1.12.2
• Forge: 14.23.1.2575
• Refined Storage: 1.5.30 (confirmed broken in 1.5.31)

This issue occurs on servers.

This has been fixed by #1610.