Fix cursor type in RedisModuleScanCursor (#10698)

Changed cursor's type from `int` to `unsigned long`
allows handling database or key with more than 2^31 elements

src/module.c

@@ -9809,7 +9809,7 @@ typedef struct {
 } ScanCBData;
 
 typedef struct RedisModuleScanCursor{
-    int cursor;
+    unsigned long cursor;
     int done;
 }RedisModuleScanCursor;