Clear OSD + surfaces when removing a Lua script (resolves #3014)

they were already being cleared when closing the Lua Console
note the "Erase Stale/Stuck Lua Drawing Layers" button does not clear OSD,
leaving that as it is for now

src/BizHawk.Client.EmuHawk/tools/Lua/LuaConsole.cs

@@ -948,6 +948,8 @@ namespace BizHawk.Client.EmuHawk
 				}
 
 				UpdateDialog();
+				DisplayManager.ClearApiHawkSurfaces();
+				DisplayManager.OSD.ClearGuiText();
 			}
 		}