fix error with access behavior

apps/explorer/lib/explorer/staking/epoch_counter.ex

@@ -64,7 +64,7 @@ defmodule Explorer.Staking.EpochCounter do
   def handle_info({:chain_event, :blocks, :realtime, blocks}, state) do
     new_block_number =
       blocks
-      |> Enum.map(& &1[:number])
+      |> Enum.map(&Map.get(&1, :number, 0))
       |> Enum.max(fn -> 0 end)
 
     case :ets.lookup(@table_name, @epoch_end_key) do

apps/explorer/test/explorer/staking/epoch_counter_test.exs

@@ -37,7 +37,7 @@ defmodule Explorer.Staking.EpochCounterTest do
 
     event_type = :blocks
     broadcast_type = :realtime
-    event_data = [%{number: 881}]
+    event_data = [%Explorer.Chain.Block{number: 881}]
 
     set_mox(11, 960)
     Publisher.broadcast([{event_type, event_data}], broadcast_type)