No, it’s not phishing, it’s legit, the header match with google and the link goes to https://accounts.google.com/AccountChooser/signinchooser?continue=https%3A%2F%2Fadmin.google.com%2Fac%2Fac%2Falert%2Fdetails%3FalertId%3D3…
Why not just write the message there instead of letting me login to watch the important notification???
Public services here do that too. But they then use a known local service for that.