Problem/Motivation
On the single item config export form (/admin/config/development/configuration/single/export), one can change the configuration type in order to see configuration names that match the type, before then choosing a configuration name to be shown the item's export code. However, once a configuration name has been chosen, changing the configuration type leaves the export code in place, which can be confusing UX.
Proposed resolution
The proposed solution is to clear the export field value when the configuration type is changed. This will prevent confusion and allow the user to then choose a configuration name for the newly-select type.
Remaining tasks
A patch for this change is attached, and review/testing/comment would be appreciated. The change does not alter the UI or other behaviour on the form.