CVE-2026-11993 Fix authenticated members disabling file content indexing server-wide via extraction pool exhaustion

Mattermost versions 11.9.x = 11.9.0, 11.8.x = 11.8.4, 11.7.x = 11.7.7, 10.11.x = 10.11.22 fail to properly enforce the limit of concurrent files being processed and handled failed files, which allows a user with permission to upload files to spawn more goroutines than intended and block the...