udevadm-trigger: reject invalid wait-daemon timeout

Return from argument parsing when --wait-daemon= cannot be parsed.

This matches the other timeout options.

Reproducer:
  udevadm trigger --dry-run --wait-daemon=bad

Before:
  Failed to parse timeout value 'bad', ignoring: Invalid argument

Follow-up:
  2001622c58

test/units/TEST-17-UDEV.sanity-check.sh

@@ -282,6 +282,7 @@ udevadm trigger --parent-match /sys/class/net/$netdev --name-match /dev/null
 udevadm trigger --initialized-match
 udevadm trigger --initialized-nomatch
 udevadm trigger -w
+(! udevadm trigger --dry-run --wait-daemon=bad)
 udevadm trigger --uuid /sys/class/net/$netdev
 udevadm settle -t 300
 udevadm trigger --wait-daemon