When entering custom input, layout issues may be seen

[TheWitness]

Describe the bug

When you have a Graph Template that uses custom items from columns other than the 'task_item_id', the create graphs page will not show a header as with the image below.

This rendering is not accurate, and should be showing a header.

To Reproduce

Steps to reproduce the behavior:

1. Create a Graph Template with an override for color_id

2. Create a Graph with this Template

3. Note, there is not table header as in the example above. Also the html does not pass w3 validation

Expected behavior

Cacti should render proper HTML with headers where they are expected to be.