fix: use felt252 size and u8 size to compute length and offset

starknet/src/types/strategy.cairo

@@ -44,10 +44,10 @@ impl StoreFelt252Array of Store<Array<felt252>> {
         // Read the stored array's length. If the length is superior to 255, the read will fail.
         let len: u8 = Store::<u8>::read_at_offset(address_domain, base, offset)
             .expect('Storage Span too large');
-        offset += 1;
+        offset += Store::<u8>::size();
 
         // Sequentially read all stored elements and append them to the array.
-        let exit = len + offset;
+        let exit = (len * Store::<felt252>::size()) + offset;
         loop {
             if offset >= exit {
                 break;
@@ -68,7 +68,7 @@ impl StoreFelt252Array of Store<Array<felt252>> {
         // // Store the length of the array in the first storage slot.
         let len: u8 = value.len().try_into().expect('Storage - Span too large');
         Store::<u8>::write_at_offset(address_domain, base, offset, len);
-        offset += 1;
+        offset += Store::<u8>::size();
 
         // Store the array elements sequentially
         loop {