chore: set resolve.mainFields and resolve.conditions for SSR environment

[sapphi-red]

Description

Since vitejs/vite#18395, ssr.resolve.conditions/ssr.resolve.mainField(this does not exist yet, maybe needed?) does not inherit resolve.conditions/resolve.mainFields anymore.
This PR sets those values by environments.ssr.resolve.conditions/environments.ssr.resolve.mainFields.

This PR should fix the ecosystem-ci fail for vite-plugin-react.

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commit: 45c904b

[hi-ogawa]

Thanks!
I'm testing Vite 6 in #6867 and had a issue with immutable package, but fixed after adding this. It looks like it was due to Vitest picking up module field.