Fix image ID clash in media selector

[pierlon]

Summary

Fixes a special case when the media library state is initialized first, then the Unsplash state, the Unsplash image models override the ones from the media library where the model IDs are the same.

Demo

Before

After

Checklist

• [ ] My pull request is addressing an open issue (please create one otherwise).
• [ ] My code is tested and passes existing tests.
• [x] My code follows the Contributing Guidelines (updates are often made to the guidelines, check it out periodically).

[derekherman]

@pierlon The lock file was wrong. Should be fixed now.