### Godot version

master

### System information

Ubuntu

### Issue description

I think one of the recent changes wrapped the project converter in `#ifndef DISABLE_DEPRECATED` but missed the coresponding code in `main.cpp` (and potentially other places).
```
main/main.cpp: In static member function 'static bool Main::start()':
main/main.cpp:2551:33: error: 'ProjectConverter3To4' was not declared in this scope
 2551 |                 int exit_code = ProjectConverter3To4(converter_max_kb_file, converter_max_line_length).convert();
      |                                 ^~~~~~~~~~~~~~~~~~~~
main/main.cpp:2556:33: error: 'ProjectConverter3To4' was not declared in this scope
 2556 |                 int exit_code = ProjectConverter3To4(converter_max_kb_file, converter_max_line_length).validate_conversion();
```

### Steps to reproduce

for instance, try to compile with `deprecated = "no"` in your `custom.py`.

### Minimal reproduction project

n/a
GLOBAL_DEF("rendering/rendering_device/driver", default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/rendering_device/driver.windows", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/rendering_device/driver.linuxbsd", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/rendering_device/driver.android", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/rendering_device/driver.ios", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/rendering_device/driver.macos", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		driver_hints = "";
#ifdef GLES3_ENABLED
		driver_hints += "opengl3";
#endif
		default_driver = driver_hints.get_slice(",", 0);
		GLOBAL_DEF("rendering/gl_compatibility/driver", default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/gl_compatibility/driver.windows", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/gl_compatibility/driver.linuxbsd", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/gl_compatibility/driver.web", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/gl_compatibility/driver.android", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/gl_compatibility/driver.ios", PROPERTY_HINT_ENUM, driver_hints), default_driver);
		GLOBAL_DEF(PropertyInfo(Variant::STRING, "rendering/gl_compatibility/driver.macos", PROPERTY_HINT_ENUM, driver_hints), default_driver);
	}
	
#ifdef VULKAN_ENABLED
	renderer_hints = "forward_plus,mobile";
	default_renderer_mobile = "mobile";
#endif
	
#ifdef GLES3_ENABLED
	if (!renderer_hints.is_empty()) {
		renderer_hints += ",";
	}
	renderer_hints += "gl_compatibility";