fix: Fix plugin settings

[ChFlick]

Fixes #626

The main problem was that

config.set('plugins', {
  ...config.get('plugins'),
  [name]: values,
})

was called before the value of values was updated.
Solution: moved it to useEffect with the dependency of values.

Furthermore, the dropdown settings weren't rendered correctly as the Select Component expects one of the options as its value (like { label: 'string', value: 'string' }) and not just a string. So when a string option is used, find the corresponding option.

[dubisdev]

LGTM 🚀