chore: remove unused fetch_and_lock_by_hashes/1 public function

apps/explorer/lib/explorer/chain/pending_block_operation.ex

@@ -35,19 +35,6 @@ defmodule Explorer.Chain.PendingBlockOperation do
     |> unique_constraint(:block_hash, name: :pending_block_operations_pkey)
   end
 
-  @doc """
-  Returns all pending block operations with the `block_hash` in the given list,
-  using "FOR UPDATE" to grab ShareLocks in order (see docs: sharelocks.md)
-  """
-  def fetch_and_lock_by_hashes(hashes) when is_list(hashes) do
-    from(
-      pending_ops in __MODULE__,
-      where: pending_ops.block_hash in ^hashes,
-      order_by: [asc: pending_ops.block_hash],
-      lock: "FOR UPDATE"
-    )
-  end
-
   def block_hashes do
     from(
       pending_ops in __MODULE__,