Usage : 'com.adobe.reactor.dataElementCookiesMigrated' cookie help with migration between DTM and Launch. Cached data element values were stored in cookies in DTM, whereas they are stored in web storage in Launch.
Function : After migration from DTM to Launch, when Launch script runs on website, system look to see if 'com.adobe.reactor.dataElementCookiesMigrated' already exists in local storage. If it doesn’t, then system read the cookies (created by DTM) for cached data element values and copy them to web storage as long as data elements by the same name exist in Launch. System then set `com.adobe.reactor.dataElementCookiesMigrated` in local storage so we don’t attempt to copy them again.