fix: avoid packageJson without name in resolveLibCssFilename

[Jinjiang]

Description

Fix the issue when there is no package name in package.json.

which causes errors like below:

[vite:css-post] Cannot read properties of undefined (reading '0')
[vite:css-post] Cannot read properties of undefined (reading '0')
    at getPkgName (/.../node_modules/vite/dist/node/chunks/dep-M1IYMR16.js:10488:14)
    at resolveLibCssFilename (/.../node_modules/vite/dist/node/chunks/dep-M1IYMR16.js:50127:30)

[patak-dev]

Why does the package.json doesn't have a name? It is required:

A package.json file must contain "name" and "version" fields.

Maybe we should improve the error instead saying that the package.json is malformed?

[silverwind]

name and version may be required in the docs, but as far as the npm client is concerned {} is a valid package.json, so I suggest to treat is gracefully.

I think those requirements are only enforced for published packages.