Squashed 'extensions/DFDiagram/' changes from 8696bb3..2b3a7f1

2b3a7f1 Attempt to fix ResourceLoader JS issues on 1.20

git-subtree-dir: extensions/DFDiagram
git-subtree-split: 2b3a7f1481a124d7457e10d6518882db77f6239f
Merge commit '2314ea0cd243a3287c539f704001274152b41e60'