fix(addon-docs): correctly sanitize item.type.elements to item.type.value
fix(addon-docs): correctly sanitize item.type.elements to item.type.value

which now only happens if the elements entry is present
and also is applied at the correct nesting level of the
item object.

refs #11944

kadirahq/react-storybook,kadirahq/react-storybook,storybooks/storybook,storybooks/storybook,storybooks/react-storybook,storybooks/react-storybook,storybooks/storybook,storybooks/storybook,storybooks/storybook,storybooks/react-storybook,storybooks/storybook,storybooks/react-storybook,storybooks/storybook