### 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
} else if (args[i] == "--doctool") {
				doc_tool_path = args[i + 1];
				if (doc_tool_path.begins_with("-")) {
					/
					doc_tool_path = ".";
					parsed_pair = false;
				}
			} else if (args[i] == "--export-release") {
				editor = true; /
				_export_preset = args[i + 1];
			} else if (args[i] == "--export-debug") {
				editor = true; /
				_export_preset = args[i + 1];
				export_debug = true;
			} else if (args[i] == "--export-pack") {
				editor = true;
				_export_preset = args[i + 1];
				export_pack_only = true;
#endif
			} else {
				/
				parsed_pair = false;
			}
			if (parsed_pair) {
				i++;
			}
		}
#ifdef TOOLS_ENABLED
		/
		else if (args[i] == "--doctool") {