fix(resolve): use DEFAULT_EXTENSIONS when resolving file from node_modules

[zscumt123]

fix #11467

Description

in this case

//vite.config.ts
import { defineConfig } from "vite";
export default defineConfig({
  resolve: {
    extensions: ['.ts']
  }
})

some dependence from node_modules, package.json without file extension

{
  "main": "./lib/form_data",
  "browser": "./lib/browser",
}

this can cause dependency resolved fail

---

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[patak-dev]

I don't know if this is the best thing with the current DEFAULT_EXTENSIONS, because users aren't able to avoid checking for ts or jsx in node_modules after this PR and could affect perf in some projects.

If we move forward, maybe we could do it in Vite 5 and have something like DEFAULT_NODE_MODULES_EXTENSIONS (no .ts, .jsx, etc) and a new option resolve.nodeModulesExtensions?

[bluwy]

In the last meeting, we discussed where this could be good for users to opt-in to stricter extensions in their source code, while still having node_modules work.

Rebased this, and I realized the previous implementation isn't exactly correct, because some createResolver can define their own set of extensions to resolve, e.g. CSS extensions only. We only want to fallback to DEFAULT_EXTENSIONS in node_modules if we're using the same extensions specified in resolve.extensions user config, which I've updated to do so.

I'm not very confident with the new changes, I think this needs some more tests. Marking as draft for now.