Use federated modules in workers

[bollwyvl]

Problem

The workers currently don't participate in module federation, so they get key upstream kernel-level packages fixed at build time, e.g. @jupyterlite/contents. This makes it hard to test PRs on jupyterlite, and result in a few hundred extra kb on disk when loaded.

Proposed Solution

Figure out how to change the webpack configuration to make these workers consume upstream

Additional context

Some related comments:

• https://github.com/jupyterlite/jupyterlite/pull/1723#issuecomment-3271514184

[jtpio]

Linking to an upstream issue where this was discussed: https://github.com/jupyterlab/jupyterlab/issues/10197