It is pointless (and quite confusing) to create a Blueprint Library plugin, that cannot be used in shipping build.
The plugin type is set in SNewPluginWizard::WritePluginDescriptor().
Related to [Link Removed]
Open Plugin Browser Tab in editor.
Create new plugin.
See in .uplugin file, that the type is Developer.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-37027 in the post.