Add Redot as a project feature to protect Redot projects

(cherry picked from commit 02abb1e8a1)

core/config/project_settings.cpp

@@ -80,6 +80,7 @@ String ProjectSettings::get_imported_files_path() const {
 const PackedStringArray ProjectSettings::get_required_features() {
 	PackedStringArray features;
 	features.append(VERSION_BRANCH);
+	features.append("Redot");
 #ifdef REAL_T_IS_DOUBLE
 	features.append("Double Precision");
 #endif