In Graph Management, filtering for "Device: None" shows all graphs

# Describe the bug

in Cacti 1.2.21 (and 1.2.20, not sure about earlier versions), when filering "Device: None" in Graph Management, all graphs are shown.

Debian 11, Php 7.4

## To Reproduce

- Go to Graph Management - Graphs
- Select: Device None
- All graphs are shown

## Expected behavior

Only "Non Device Graphs" should be shown