### 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
while (I) {
#ifdef MACOS_ENABLED
		
		
		if (I->get().begins_with("-psn_")) {
			I = I->next();
			continue;
		}
#endif
		List<String>::Element *N = I->next();
#ifdef TOOLS_ENABLED
		if (I->get() == "--debug" ||
				I->get() == "--verbose" ||
				I->get() == "--disable-crash-handler") {
			forwardable_cli_arguments[CLI_SCOPE_TOOL].push_back(I->get());
			forwardable_cli_arguments[CLI_SCOPE_PROJECT].push_back(I->get());
		}
		if (I->get() == "--single-window") {
			forwardable_cli_arguments[CLI_SCOPE_TOOL].push_back(I->get());
		}
		if (I->get() == "--audio-driver" ||
				I->get() == "--display-driver" ||
				I->get() == "--rendering-method" ||
				I->get() == "--rendering-driver") {
			if (I->next()) {
				forwardable_cli_arguments[CLI_SCOPE_TOOL].push_back(I->get());
				forwardable_cli_arguments[CLI_SCOPE_TOOL].push_back(I->next()->get());
			}
		}
#endif