In Articulation Body you can see Limit settings even when they do nothing

To reproduce:
1. Create a new project
2. Add a Game Object to the scene
3. Add Articulation Body to the game obect
4. Set Swing Y, Swing Z and Twist settings to free
Expected result: Lower and Upper Limit fields are not visible
Actual result: The fields are visible

Reproduced on: 2020.1.0a15 (feature introduced in this version)