Unable to override settings in settings.php

Problem/Motivation

It is not possible to override the location of the binaries using settings.php

Steps to reproduce

If the binaries are in a location other than /usr/bin, add the following to an included settings.local.php file

$config['php_ffmpeg.settings']['ffmpeg_binary'] = '/var/www/custom_location/ffmpeg';
$config['php_ffmpeg.settings']['ffprobe_binary'] = '/var/www/custom_location/ffprobe';

The location for the binaries is still derived from the module settings rather from the overridden config set in the settings.php file.

Proposed resolution

Change the constructor of the PHPFFMpegFactory calss to use the 'get' method of the config factory rather than 'getEditable'.