No, this is wrong. As the others have said, "Brückentag" is a general term for non-holidays, and it doesn't even apply here as Friday is the holiday and not Thursday.

Good Friday is also still very significant in its religious purpose here, so calling it "bridge day", even if it applied, would be disrespectful.

(Which doesn't keep the racing/modding community from having their own "Car Freitag" on that day...)