Clicking a label without creating an arrow in relationship tagging breaks the annotator

[amauboussin]

To reproduce, click one of the labels before clicking and dragging between two words in relationship tagging mode. After clicking the label, it is impossible to label anything else. I noticed that this adds an empty relationship to the output, so I'm guessing it messes up the component state in some way.

In case it is browser-specific issues, here is a video showing the bug using the code playground as an example: https://www.loom.com/share/cc3c1dbb74f6491b9b0eb68f31052a07

I am on Chrome on OS X Big Sur.