Head over to your Garry's Mod folder, it should be common knowledgement but to find it you can go to your library, right click on Garry's Mod > Manage > Browse local files, then head over to garrysmod/lua/menu and in menu folder there should be errors.lua.

The path should be like this

"Steam\steamapps\common\GarrysMod\garrysmod\lua\menu\errors.lua"

open the file with your notepad and just remove every bit of text in it, basically just leave it empty, then just ctrl+s to save it.

Only thing this will do is making it so the notification for lua error can't appear, it will still appear on your console because if something is constantly spamming an error message most of the time it means it is indeed broken, otherwise it's usually just useless errors that don't affect your gameplay.

This will NOT fix any broken mods