Remove sideEffects: false from packages with CSS modules

[valerybugakov]

Context

The CSS rules order in the production environment differs from what we have in the development env because of the combination of the mini-css-plugin and sideEffects: false.

See this comment on the unresolved issue:

In addition to that, mini-css-plugin makes no strong guarantee about the order of independent CSS files. It tries its best to keep the importing order, but there are some cases where this is not followed, e. g. because modules are split into multiple css bundles.
I would recommend to not rely on CSS order between multiple files in general.

/cc @taylorsperry @muratsu