UI: Fix React unique key warning when using renderLabel

[ghengeveld]

Issue: #14102

What I did

Somehow React thinks the result of invoking renderLabel is an array and logs a 'key prop' warning. I suspect this happened because we were calling the renderLabel function outside of a React tree context, passing the result along in the story data before injecting it elsewhere in a React tree. Needless to say the only way I was able to fix it without affecting the user-facing API was by passing the function itself along in the story data and invoking it where we're rendering it. It might actually be more memory efficient because we're passing the same function reference for each story.

How to test

• Is this testable with Jest or Chromatic screenshots? No
• Does this need a new example in the kitchen sink apps? No
• Does this need an update to the documentation? No

If your answer is yes to any of these, please make sure to include it in your PR.

[shilman]

💯

[shilman]

@ghengeveld any thoughts on this diff https://www.chromatic.com/test?appId=5a375b97f4b14f0020b0cda3&id=60468a9c335209002113c1a4