DownloadLatestAlLanguageExtension concurrency mutex exception

[lktraser]

❔What, Why & How

Problem
On build servers running concurrent pipeline agents, DownloadLatestAlLanguageExtension sporadically throws:
Exception calling ".ctor" with "2" argument(s): "Access to the path 'DownloadAlLanguageExtension' is denied."

Root cause: named mutexes created without an explicit security descriptor are placed in a session-scoped namespace and inherit the creator's DACL. When Azure DevOps agents run as a domain user or service account, the pipeline host performs Windows impersonation that lands each agent job in a different logon session. The second process attempting to open the mutex gets access denied — not because of file permissions, but because the kernel object was created in another session's namespace. This is the same class of problem originally reported in #1088 and again in #3164.

Fix
Prefix mutex name with Global\ — places it in the global kernel namespace, shared across all logon sessions
Attach a MutexSecurity ACL granting FullControl to Everyone (via WellKnownSidType.WorldSid) so any process can open the existing mutex regardless of session
Tested

Verified on a Windows Server build host with multiple Azure DevOps agents running concurrently under a domain user service account.

✅ Checklist

• [ X] Add tests (Tests / LinuxTests) - existing tests should cover this
• [ X] Update ReleaseNotes.txt
• [ X] Add telemetry - no new functionality so no new telemetry