Replace text on Variant Reporting to reflect decisions for "Variant IG Lite"

The descriptive text below the Variant model should be updated to reflect decisions made through discussions about "IG Lite" found in this document: https://docs.google.com/document/d/15g1rngmgFoE8_i7UGpXRpISkOCrd1QCoQBg9REY80EI/edit#

This is a working document and once it's finished, it can replace/add to the text on the Variant Reporting page to guide readers.