Do not prevent caching of 403/404

The patch can be found here: https://git.drupalcode.org/issue/cache_control_override-3364452/-/commit...

I tried the patch on https://master-oowrqeonft6ldtavsemgri12jdeiaq35.tugboatqa.com/ and confirms it adds a Cache-Control: max-age=3600, public header on 404 pages.

I also tested locally that setting $settings['cache_ttl_4xx'] changes the duration.

Got merge conflicts with the latest dev branch so I've created a new patch (no access to alter the MR)

I think you should have a "get push access" green button above, to alter the MR.