Extract sound effects enum into its own file

Avoids depending on all of `effects` in places where we only need the
enum.

Source/monstdat.h

@@ -5,7 +5,9 @@
  */
 #pragma once
 
+#include <cstddef>
 #include <cstdint>
+#include <string>
 #include <vector>
 
 #include "cursor.h"

Source/spelldat.h

@@ -13,7 +13,7 @@
 
 #include <expected.hpp>
 
-#include "effects.h"
+#include "sound_effect_enums.h"
 #include "utils/enum_traits.h"
 
 namespace devilution {

Source/textdat.h

@@ -7,7 +7,7 @@
 
 #include <cstdint>
 
-#include "effects.h"
+#include "sound_effect_enums.h"
 
 namespace devilution {