String values in config files that contain embedded quotes are not handled correctly

If a config object specified via the .config option to yargs contains a value that starts and ends with quotes, yargs strips those quotes, due to this code here:

https://github.com/yargs/yargs-parser/blob/50b54ae66aed4240021ba8fed9e98fec3f8d07ef/lib/yargs-parser.ts#L608

That seems like confusing, and undesirable behavior, and makes it difficult to pass values containing embedded quotes.

For example:

console.log(require('yargs').config({a: JSON.stringify('hello')}).parse());

This prints:

{ _: [], a: 'hello', '$0': 'yargs-bug.js' }

But I would expect it to instead print:

{ _: [], a: '"hello"', '$0': 'yargs-bug.js' }

I would suggest that when parsing already-split arguments, e.g. from process.argv, or when processing a config file, quotes should never be stripped, and no additional splitting should ever occur. The only time stripping of quotes should happen is when parsing an unsplit string. In that case, the string should be parsed into an array of strings using shell-style parsing, and then parsing should proceed using the resultant array, and do no further splitting or quote handling.

Review lib/yargs-parser.ts at line 608 and the .config/process.argv parsing entry points. Reproduce the JSON.stringify example, then verify that already-split values preserve embedded quotes while only unsplit strings receive shell-style quote handling.