Meta: Shellcheck ignore for our expr use (SC2307)

Author: https://github.com/nathanbw
Commit: https://github.com/SerenityOS/serenity/commit/cdc5ed2fb5
Pull-request: https://github.com/SerenityOS/serenity/pull/13776
Reviewed-by: https://github.com/BertalanD ✅
Reviewed-by: https://github.com/timschumi
Reviewed-by: https://github.com/trflynn89

Meta/build-image-qemu.sh

@@ -66,7 +66,7 @@ else
 fi
 
 disk_usage() {
-    # shellcheck disable=SC2003
+    # shellcheck disable=SC2003,SC2307
     expr "$(${GNUDU} -sk --apparent-size "$1" | cut -f1)"
 }