[GPUP][macOS] Add read access to sysctl properties to match iOS

https://bugs.webkit.org/show_bug.cgi?id=273704
<rdar://122962852>

Reviewed by Per Arne Vollan.

In Bug 236018 we added `kern.bootargs` to the iOS sandbox to reduce telemetry, and because it
was needed to support control of certain system behaviors at boot time.

We should have added this to the macOS sandbox at the time, but did not.

This patch brings the two sandboxes into alignment, and avoids sandbox telemetry that hides
more useful findings.

* Source/WebKit/GPUProcess/mac/com.apple.WebKit.GPUProcess.sb.in:

Canonical link: https://commits.webkit.org/278364@main

Source/WebKit/GPUProcess/mac/com.apple.WebKit.GPUProcess.sb.in

@@ -1,4 +1,4 @@
-; Copyright (C) 2010-2023 Apple Inc. All rights reserved.
+; Copyright (C) 2010-2024 Apple Inc. All rights reserved.
 ;
 ; Redistribution and use in source and binary forms, with or without
 ; modification, are permitted provided that the following conditions
@@ -214,6 +214,7 @@
         "hw.product"
         "hw.target"
         "hw.vectorunit"
+        "kern.bootargs"
         "kern.hostname"
         "kern.hv_vmm_present"
         "kern.iossupportversion"