fix: resolve import exports for unknown Rspack dependencies

[nikita-jpg]

What

• Add the import condition to Rspack resolution for dependencies classified as unknown.
• Keep the existing require and module conditions.
• Leave Webpack resolution unchanged.

Why

A JavaScript package can contain ESM imports while omitting type: module. Rspack may classify a nested dependency from such a package as unknown. When that dependency targets a public package subpath with separate import and require exports, the ESM branch is not considered and resolution can fail.

Scoping the additional condition to byDependency.unknown fixes this case without changing resolution conditions globally.

Reproduction example

@gravity-ui/chartkit@8.1.0 is an affected real-world package. Its Yagr plugin imports the public @gravity-ui/yagr/react subpath, with @gravity-ui/yagr@5.2.0 selected in the dependency graph.

An application built with Rspack can fail while bundling this dependency graph:

Package subpath './dist/react' is not defined by "exports" in @gravity-ui/yagr/package.json

With the import condition enabled for unknown dependencies, Rspack selects Yagr's public ESM export and the same dependency graph builds successfully.

Testing

• pnpm test --runInBand
• pnpm typecheck
• pnpm lint
• pnpm build
• pnpm --filter "@examples/*" build