It's totally normal behaviour. All kids do it.

Don't ignore your kid. It's such a simple situation.

Just respond to them. A little yes or no is enough. They don't need your full attention. They just need confirmation you are listening to them. It doesn't matter if you actually did or not. Just pretend to and answer with generic answers: "really?" "did you now?" "that's awesome"

If you don't, they'll either keep going, or eventually you'll strain your relationship with them. Pretty basic stuff really.