Moderate a single draft error infinite loop

Problem/Motivation

When trying to moderate on an item that only has 1 draft and nothing to diff, the system loops and WSOD, and fills the log with notices about missing $revision_ids[ (id) ]

Steps to reproduce

For my instance it was just - moderate a single draft of a normal content type.

Proposed resolution

I changed

// If there are only 2 revision return an empty row.
if ($revisions_count == 2) {
return [];
}

// If there are less-than 2 revision return an empty row.
if ($revisions_count <= 2) {