fix: add attribute merging to logCheckoutOptionEvent#64

khushi1033 wants to merge 4 commits intodevelopmentmparticle-integrations/mparticle-javascript-integration-google-analytics-4:developmentfrom

fix/SDKE-781-add-attribute-merging-to-logCheckoutOptionEventmparticle-integrations/mparticle-javascript-integration-google-analytics-4:fix/SDKE-781-add-attribute-merging-to-logCheckoutOptionEventCopy head branch name to clipboard