Astro hoists multiple step scripts from Wizard even when the step is not
rendered on the current order page. Several steps bound DOM elements at load
time with no presence check, causing null addEventListener errors on unrelated
order pages.
Add step-presence guards to the obvious offenders used by the shared wizard:
IccImportStep, Block6CertStep, WirelessStep, BundledServiceStep, CPNIStep,
and LNPARegionStep.