Volar adds ".js" extension when autoimporting components

[sheremet-va]

Version: v1.7.0

When typescript.preferences.importModuleSpecifierEnding and javascript.preferences.importModuleSpecifierEnding is enabled (js), VSCode auto imports Vue components with .vue.js extension instead of just .vue (when typing component name in script or template blocks).

Reproduction: https://github.com/sheremet-va/volar-bug-extension

[sheremet-va]

Another issue is that Volar uses .js extension when importing any file inside Vue components, but it keeps .ts extension when importing inside TypeScript file (this is allowed with allowImportingTsExtensions compiler option).

It should just keep an extension. "js" value in importModuleSpecifierEnding means "to use the file extension" as far as I understand.

This worked as expected in #2518