Make all JS files editable in the MODX manager in PHP 8.4

[halftrainedharry]

What does it do?

Adds application/javascript to the list of non-binary MIME types.

Why is it needed?

In PHP 8.4 some *.js files return the MIME type application/javascript. The same files used to return text/plain in previous PHP versions.
(I believe finfo::file is used in the code to determine the MIME type, but I couldn't figure out what exactly changed in the new PHP version.)

How to test

• Use PHP 8.4
• Create a new JS file in the default file system, e.g. test.js
• Enter the following content:

(function() {
	console.log('test');
}());

• Make sure that this file is still editable in the MODX manager ("Files" tab).

Related issue(s)/PR(s)

Resolves #16730