Allow custom files to bypass the integrity check

[!TIP]

Help move this idea forward

• Use the 👍 reaction to show support for this feature.
• Avoid commenting unless you have relevant information to add; unnecessary comments create noise for subscribers.
• Subscribe to receive notifications about status changes and new comments.

Is your feature request related to a problem? Please describe.
Integrity check failes

Describe the solution you'd like
Add custom files to the allowed files to stop triggering the integrity.check fails

Describe alternatives you've considered
Disable integrity.check

Additional context

Technical information
=====================
The following list covers which files have failed the integrity check. Please read
the previous linked documentation to learn more about the errors and how to fix
them.

Results
=======
- core
	- EXTRA_FILE
		- .well-known/security.txt

Raw output
==========
Array
(
    [core] => Array
        (
            [EXTRA_FILE] => Array
                (
                    [.well-known/security.txt] => Array
                        (
                            [expected] => 
                            [current] => 7a1bfaad9dd849e3697ed64fc5d2049fc3101fd7461a3ba4c9eb71e2ebe5582075211d20e42e819ff675258e79c7d1bcefb563a197eecdc8e9b83bba4fb91d76
                        )

                )

        )

)

Start by tracing the integrity-check path that reports EXTRA_FILE for .well-known/security.txt, then review how allowed files are defined and validated. Define how custom-file allowances should be configured without weakening checks for unapproved files, and verify the resulting integrity-check behavior with the relevant existing test coverage.