[scoped-custom-element-registry] Add module flag to scoped-custom-element-registry

[alangdm]

When trying to use @webcomponents/scoped-custom-element-registry through unpkg using the ?module flag, unpkg throws an error since the package doesn't include a module entry point

While removing the ?module flag in unpkg works when using this package directly, this is still a problem when using packages that depend on this package such as @open-wc/scoped-elements

I noticed that similar polyfills have solved this issue by adding a module entry point to the package.json so I tried doing the same

Please let me know if you would prefer the module entry point to be the unminified file instead

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[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.