[Mappings Editor] Re-render when default values changes

[jloleysens]

On this PR #64049 I noticed that when defaultValues for form data changes, we do not re-render the form with the new default values.

I think this makes sense for something like "defaultValues", but my question is, would it make sense to provide users a way of re-setting form values externally?

The primary use case I can think of is situations like #64049, where we want to pre-populate a form and that the values used to pre-populate are themselves subject to change.

Workarounds I can think of: unmount and remount component with new defaultValue or calling form.setValue when new props come in.

[elasticmachine]

Pinging @elastic/es-ui (Team:Elasticsearch UI)

[sebelga]

@jloleysens Just seeing this issue now. It's a great point and I've been thinking about adding that functionality inside the lib.

For now, the workaround is doing it from the consumer perspective, like we do in the configuration form of the mappings editor https://github.com/elastic/kibana/blob/master/x-pack/plugins/index_management/public/application/components/mappings_editor/components/configuration_form/configuration_form.tsx#L133

When the value changes, we reset the form (whose defaultValue is set to be value). It's not very clean and that's why I'd like to do it from inside the form.

[sebelga]

Closing as this has been fixed in #75302