Fix BGMXPCHelper not launching due to Gatekeeper in macOS 14.5.

The previous fix was removing the quarantine attribute from the
BGMXPCHelper.xpc dir, but in 14.5 its contents also get the attribute.
(I haven't tested in earlier versions.) This new fix removes the
attribute from the contents as well.

pkg/postinstall

@@ -32,6 +32,13 @@ function log {
     echo "$@"
 }
 
+function log_output {
+    while read line
+    do
+        log "$line"
+    done < /dev/stdin
+}
+
 coreaudiod_plist="/System/Library/LaunchDaemons/com.apple.audio.coreaudiod.plist"
 dest_volume="$3"
 xpc_helper_install_path="$(bash safe_install_dir.sh -y)"
@@ -52,7 +59,9 @@ cp -Rf "BGMXPCHelper.xpc" "$xpc_helper_install_path"
 # TODO: I think, ideally, we should use the new Service Management API to install BGMXPCHelper,
 #       which would probably avoid this issue. See
 #       <https://developer.apple.com/documentation/servicemanagement/updating_your_app_package_installer_to_use_the_new_service_management_api>.
-sudo xattr -d com.apple.quarantine "${xpc_helper_install_path}/BGMXPCHelper.xpc"
+log "Removing com.apple.quarantine attribute from BGMXPCHelper."
+sudo xattr -dr com.apple.quarantine "${xpc_helper_install_path}/BGMXPCHelper.xpc" 2>&1 | log_output
+ls -lah@ "${xpc_helper_install_path}/BGMXPCHelper.xpc" 2>&1 | log_output
 
 # TODO: Fail the install and show an error message if this fails.
 bash "post_install.sh" "$xpc_helper_install_path" "BGMXPCHelper.xpc/Contents/MacOS/BGMXPCHelper" "."