fs: extract path conversion and validation to getValidatedPath

Almost all path validations within our file system are combined with:
```js
path = toPathIfFileURL(path);
validatePath(path);
```

So simply extracted them out into `getValidatedPath` function to
`internal/fs/utils.js` to DRY up the code and reduce duplicating them.

PR-URL: nodejs#27656
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anto Aravinth <anto.aravinth.cse@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>