Simplify archlinux upgrade check

misc/upgrades-installed-check

@@ -29,7 +29,7 @@ elif [ -e /etc/arch-release ]; then
     set -o pipefail
     checkupdates_output="$(checkupdates 2>&1)"
     exit_code="$?"
-    echo "$checkupdates_output" | { grep -F -- '->' || true; } | [ "$(wc -L)" -eq "0" ] && echo "true" || echo "false"
+    echo "$checkupdates_output" | grep -qF -- '->' && echo "false" || echo "true"
 else
    echo "Check not implemented for this distribution" >&2
    exit 1