"Filter unknown extensions" not honored inside archives

Description

The "Filter unknown extensions" setting is only honored in ordinary directories, not inside archives.

Expected behavior

When opening a zip file containing a file that is not compatible with any installed core, if "Filter unknown extensions" is off, I expect the file to be visible.

Actual behavior

The file is not visible, usually resulting in a zip that appears empty.

Steps to reproduce the bug

1. Disable "Filter unknown extensions"
2. Create a file with a ".a26" extension
3. Place the file in a normal directory, and also inside a ZIP
4. Ensure you do not have an Atari 2600 core installed
5. Using "Load Content", navigate to the directory on disk
6. The file appears
7. Now navigate to the ZIP file
8. The file does not appear
9. Install the "Stella" core and repeat above steps
10. The file is now visible in both the directory and ZIP

Bisect Results

I'm afraid I don't know how to use bisect.

Version/Commit

• RetroArch: 1.19.1 (cloned from github an hour ago)

Environment information

• OS: Windows 11 x64
• Compiler: MSYS2 / MINGW64

Fix

This seems to be due to a missing check in menu_displaylist.c. I've added checks against filter_exts during calls to the file_archive_ methods, and in local tests it appears to fix the issue. I will submit and link a PR momentarily.

Start in menu_displaylist.c and inspect the file_archive_ methods used when browsing ZIP contents, comparing them with ordinary-directory filtering. Reproduce with a .a26 file, Filter unknown extensions disabled, and no Stella core installed. Done means the unknown file is visible inside the ZIP as it is in a normal directory.