Label frontend supports English color names, backend returns error message

Summary

Label backend does not support English color names, while frontend does.

Steps to reproduce

1. Edit a label
2. Change color to "orange"
3. Save label

What is the current bug behavior?

When putting in an English name for label colors, the JavaScript frontend accepts it and displays the color. The backend says "The form contains the following error: Color must be a valid color code".

What is the expected correct behavior?

Either not support English names in the frontend or support them in the backend.