Make ride_entry_get_first_non_null_ride_type() take a const ride entry

src/openrct2/ride/ride.c

@@ -8127,7 +8127,7 @@ const char * ride_type_get_enum_name(sint32 rideType)
  *  Searches for a non-null ride type in a ride entry.
  *  If none is found, it will still return RIDE_TYPE_NULL.
  */
-uint8 ride_entry_get_first_non_null_ride_type(rct_ride_entry * rideEntry)
+uint8 ride_entry_get_first_non_null_ride_type(const rct_ride_entry * rideEntry)
 {
     for (uint8 i = 0; i < MAX_RIDE_TYPES_PER_RIDE_ENTRY; i++)
     {

src/openrct2/ride/ride.h

@@ -1254,7 +1254,7 @@ bool ride_has_ratings(const Ride * ride);
 
 const char * ride_type_get_enum_name(sint32 rideType);
 
-uint8 ride_entry_get_first_non_null_ride_type(rct_ride_entry * rideEntry);
+uint8 ride_entry_get_first_non_null_ride_type(const rct_ride_entry * rideEntry);
 bool ride_type_supports_boosters(uint8 rideType);
 sint32 get_booster_speed(uint8 rideType, sint32 rawSpeed);
 void fix_invalid_vehicle_sprite_sizes();