support module references in extends (checking default tsconfig.json filename)

[holvi-sebastian]

I noticed using vitest with unplugin-swc that loading typescript configuration fails when referencing a module without filename.

Typescript itself and esbuild allow extending a tsconfig that is references as a module or path, without a filename.

E.g. when a tsconfig.json file is exported in a node_module called my-tsconfig-module (for example in a monorepo where a tsconfig module is a workspace that's symlinked to other packages as a module dependency)

Then your tsconfig can reference it as:

{
   "extends": "my-tsconfig-module"
}

And typescript will search for a /my-tsconfig-module dir in node_modules and look for a tsconfig.json file in it by default.

This PR adds a try / catch to handle this case.