Can't create or edit files when using the 'wpseo_allow_system_file_edit' to allow file editing

[polevaultweb]

• [x] I've read and understood the contribution guidelines.
• [x] I've searched for any related issues and avoided creating a duplicate issue.

Please give us a description of what happened.

My site uses the constant DISALLOW_FILE_EDIT to stop users editing plugins. This means I can't use the File Editor in the plugin. The filter wpseo_allow_system_file_edit can be used to show the menu item - great!

However, the code that actually does the creating or editing of files only checks current_user_can( 'edit_files' ) instead of using the WPSEO_Utils::allow_system_file_edit method which uses the filter.

Please describe what you expected to happen and why.

I expect to be able to actually make edits to the files when file editing is disabled but the filter 'wpseo_allow_system_file_edit' is used to allow it.

How can we reproduce this behavior?

1. define( 'DISALLOW_FILE_EDIT', true); in wp-config.php
2. can't see File editor in SEO > Tools
3. Add add_filter( 'wpseo_allow_system_file_edit', '__return_true' ); in an mu-plugin or functions.php
4. You now see the File Editor, try to make a change, eg. create robots.txt - you will see the error "You cannot create a robots.txt file."

Technical info

• If relevant, which editor is affected (or editors):

• [ ] Classic Editor
• [ ] Gutenberg
• [ ] Classic Editor plugin

• Which browser is affected (or browsers):

• [ ] Chrome
• [ ] Firefox
• [ ] Safari
• [ ] Other

Used versions

• WordPress version:
• Yoast SEO version:
• Gutenberg plugin version:
• Classic Editor plugin version:
• Relevant plugins in case of a bug:

• Tested with theme: