Fix chunk call

Signed-off-by: cyc60 <avsysoev60@gmail.com>

oracle/oracle/rewards/controller.py

@@ -223,7 +223,7 @@ async def calculate_withdrawal_rewards(
 
         chunk_size = 50000
         for block_number in range(from_block, to_block, chunk_size):
-            withdrawals_amount += self.fetch_withdrawal_chunk(
+            withdrawals_amount += await self.fetch_withdrawal_chunk(
                 validator_indexes=validator_indexes,
                 from_block=block_number,
                 to_block=min(block_number + chunk_size, to_block),