Attempt to fix server-side build by allowing module usage

[adamtaylor13]

Myself and others have run into this issue with the new (non-legacy) version of @phosphor-icons/react. I'm not really sure what the underlying difference is between this version and the older phosphor-react package, but when I made this change—suddenly my builds started working again.

Reference:
#55

[rektdeckard]

This is probably OK to do, but I am worried this might have the inverse effect for non-ESM-based build tools. Seems like some tooling respect the type field, others ignore it and have a preference when module and main fields are present, and yet others have an implicit assumption that it is CJS. I have tested locally with Next and seems fine, so will build an release for now. But monitoring for issues, and will try to write update our CI to build and run test apps across a bunch of common frameworks.

[rektdeckard]

Thanks for the fix, @adamtaylor13