Umm, I couldn't find the template you were talking about. Do you have the link to it? The only gamejam template link I can find is the one I am currently using... I found the template im currently using from the gamejam page.
https://github.com/raysan5/raylib-gamejam-template/tree/main this one, make sure you use it as a template so it will setup github actions for you, then when you push it will build linux, win, mac and web version, go to actions and download web build, it should not have the banner, if it still does, check that src/minshell.html exists and src/shell.html does not.