Toggling managed fields only works once, button becomes disabled afterwards

[petersutter]

What happened:
When attempting to show/hide managed fields by clicking on the button, the functionality works only the first time. After the initial click, the button becomes disabled and cannot be clicked again to toggle the managed fields.

What you expected to happen:

• The Show managed fields button should toggle back and forth between "Show" and "Hide" without becoming disabled.
• Users should be able to repeatedly click the button to switch between showing and hiding managed fields.

How to reproduce it (as minimally and precisely as possible):

• Open the Shoot YAML editor
• Click the button to show the managed fields. Notice it toggles correctly the first time.
• Attempt to click the button again. Observe that the button is now disabled and does not toggle.

Anything else we need to know:

Environment: