I must not be understanding this properly. Because if that's the new way we're classifying things, mammals are birds, and by extension also dinosaurs, amphibians, fish, and invertebrates. Which would mean whales really are fish after all!
Mammals didn't evolve from birds. Or even from reptiles, by modern definitions. (Some extinct animals more closely related to mammals than to extant reptiles used to be considered reptiles, but it's those, not mammals, that have been reclassified.)
But not even close to from birds; in fact, mammals are actually
older than birds.
"Amphibian" no longer includes any of the basal tetrapods. Only animals more closely related to frogs than to reptiles...which conveniently does include all extant animals that have ever been considered amphibians.
"Fish" is a term that's generally not used at all in taxonomy anymore, for precisely the reason of it not having a monophyletic definition, or any real way to make one that's not just a synonym for another existing term.
"Invertebrate" has, to my knowledge, actually never been considered a proper taxonomic group, just a "everything else" label. It literally never had any other definition besides "all animals except vertebrates".