Describe the bug
Only on develop branch

If you activate the debug mode in the wp-config.php the following message shows up in the admin:

Warning: filemtime(): stat failed for /app/wordpress/wp-content/themes/wprig/assets/js/admin/index.min.js in /app/wordpress/wp-content/themes/wprig/inc/Options/Component.php on line 64

To Reproduce
Steps to reproduce the behavior:

1. Setup wprig localy as documentend
2. Add to folling lines to the wp-config.php

define( 'WP_DEBUG', true );
define( 'WP_DEBUG_LOG', true );
define( 'WP_DEBUG_DISPLAY', true );
define( 'SCRIPT_DEBUG', true );

3. Login in to the admin page
4. The folling message appear on the top of the page:

Warning: filemtime(): stat failed for /app/wordpress/wp-content/themes/wprig/assets/js/admin/index.min.js in /app/wordpress/wp-content/themes/wprig/inc/Options/Component.php on line 64
The Options-Area wont work anymore

Expected behavior
The Options-Area should work and it should not show any error messages

Reason
In one of my previous pull requests, I renamed /assets/js/src/admin/index.js to index.jsx.

It would probably be a violation of the WPCS to use the previous extension js.

It seems that the file is no longer minified because of the new extension, or the minified file cannot be found because of the new extention.