You can’t, as it’s there for legal purposes as if you use another person’s work and it’s registered under Creative Commons (every scratch project has this license) you must credit them or else you can face takedowns/lawsuits (please note that the lawsuits part typically occurs in the real world rather than scratch)

You can't.

you can't and you don't

you're not supposed to be able to anyway because it's there to give credit to the original project you remixed. if you don't want it there, make your own game from scratch

Why do you want to remove it?

You can’t, for legal reasons and… it’s there because they made it originally.

You can't because a remix is a different version of the base project, so Scratch helps you out so you don't have to give the link for the original.