### Godot version

v4.1.rc2.official [46424488e]

### System information

Godot v4.1.rc2 - Linux Mint 20 (Ulyana) - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 2060 SUPER (nvidia; 515.105.01) - Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz (8 Threads)

### Issue description

Dragging and dropping a file to a new position inside its current folder, or onto the icon for its current folder - when that folder is the project root folder :res// - will be treated as though you were dropping a different file with the same name.

Expectation: for nothing to happen.

Also tried it in 4.0.3 and 4.1-dev3, where it behaves as expected.

https://github.com/godotengine/godot/assets/64640811/90de1120-dd92-41b8-b202-db77c343103a

### Steps to reproduce

1. New or existing project.
2. Click and drag a file in :res// in FileSystem dock.
3. Drop the file back into :res//.
4. Be prompted to overwrite or rename.

### Minimal reproduction project

N/A
const HashMap<StringName, PropertyInfo> prop_info = ProjectSettings::get_singleton()->get_custom_property_info();
	for (const KeyValue<StringName, PropertyInfo> &E : prop_info) {
		if (E.value.hint == PROPERTY_HINT_FILE) {
			String old_path = GLOBAL_GET(E.key);
			if (p_renames.has(old_path)) {
				ProjectSettings::get_singleton()->set_setting(E.key, p_renames[old_path]);
			}
		};
	}
	
	List<PropertyInfo> property_list;
	ProjectSettings::get_singleton()->get_property_list(&property_list);
	for (const PropertyInfo &E : property_list) {
		if (E.name.begins_with("autoload/")) {
			
			
			String autoload = GLOBAL_GET(E.name);
			String autoload_singleton = autoload.substr(1, autoload.length());
			if (p_renames.has(autoload)) {
				ProjectSettings::get_singleton()->set_setting(E.name, p_renames[autoload]);
			} else if (autoload.begins_with("*") && p_renames.has(autoload_singleton)) {
				ProjectSettings::get_singleton()->set_setting(E.name, "*" + p_renames[autoload_singleton]);
			}
		}
	}
	ProjectSettings::get_singleton()->save();
}
String FileSystemDock::_get_unique_name(const FileOrFolder &p_entry, const String &p_at_path) {