make Semantic-UI's AddButton not show an empty label

[LucienLeMagicien]

Reasons for making this change

The Semantic-UI theme's AddButton, which is used for ObjectFieldTemplate and ArrayFieldTemplate, currently displays an empty slot for a non-existent label:

This makes it show a square button:

Checklist

• I'm adding or updating code
  • I've added and/or updated tests. I've run npm run test:update to update snapshots, if needed.
  • I've updated docs if needed
  • I've updated the changelog with a description of the PR

I cannot run/update the tests as the build fails for me. I assume it's somehow a me issue though:

[@rjsf/core     ] > @rjsf/core@5.0.0-beta.9 build
[@rjsf/core     ] > rimraf dist && dts build --rollupTypes --format cjs,esm,umd
[@rjsf/core     ] 
[@rjsf/core     ] node:internal/modules/cjs/loader:936
[@rjsf/core     ]   throw err;
[@rjsf/core     ]   ^
[@rjsf/core     ] 
[@rjsf/core     ] Error: Cannot find module './templates.js'
[@rjsf/core     ] Require stack:
[@rjsf/core     ] - [...]/packages/core/node_modules/@babel/highlight/node_modules/chalk/index.js

the ./templates.js file is present in node_modules/chalk/, but not in packages/core/node_modules/@babel/highlight/node_modules/chalk/ (and all other dependencies depending on it). I'd appreciate guidance on this. Should I open a separate issue?

EDIT: ignore the above. Deleting the node_modules folders and re-running npm install fixed it. I assume the node_modules folders ended up in an invalid state after my first run of npm run build failed.
For the record, this is what I ran:

rm --recursive --force --verbose packages/*/node_modules
rm -rfv node_modules/
npm install

[heath-freenome]

@LucienLeMagicien Can you update the tests for this change? npm run test:update will fix the snapshots