In Minecraft Now, Agnes confirmed that Frogs will no longer eat Fireflies on the full release of 1.19. The reason of this is because a variety of fireflies are extremely deadly to Frogs in real life. I really think that this should be the case in beta 0.6 or 0.7 because it will make the lore of the Fireflies & the Frogs more relevant to the actual version of the mobs.

@Soro335 Thanks! 😊