allow mach-lookup for com.apple.system.opendirectoryd.libinfo (#3334)

in the base sandbox policy. this is [allowed in Chrome
renderers](https://source.chromium.org/chromium/chromium/src/+/main:sandbox/policy/mac/common.sb;l=266;drc=7afa0043cfcddb3ef9dafe5acbfc01c2f7e7df01),
so I feel it's fairly safe.

codex-rs/core/src/seatbelt_base_policy.sbpl

@@ -69,3 +69,8 @@
 ; Added on top of Chrome profile
 ; Needed for python multiprocessing on MacOS for the SemLock
 (allow ipc-posix-sem)
+
+; needed to look up user info, see https://crbug.com/792228
+(allow mach-lookup
+  (global-name "com.apple.system.opendirectoryd.libinfo")
+)