Add Engine.print_error_messages property to disable printing errors

Backports #48359 to 3.x.

Co-authored-by: Hugo Locurcio <hugo.locurcio@hugo.pro>

core/engine.h

@@ -101,6 +101,9 @@ public:
 	void set_frame_delay(uint32_t p_msec);
 	uint32_t get_frame_delay() const;
 
+	void set_print_error_messages(bool p_enabled);
+	bool is_printing_error_messages() const;
+
 	void add_singleton(const Singleton &p_singleton);
 	void get_singletons(List<Singleton> *p_singletons);
 	bool has_singleton(const String &p_name) const;