Fix Style/MapIntoArray cop in cli progress helper (#29884)

lib/mastodon/cli/progress_helper.rb

@@ -35,10 +35,8 @@ module Mastodon::CLI
       aggregate = Concurrent::AtomicFixnum.new(0)
 
       scope.reorder(nil).find_in_batches do |items|
-        futures = []
-
-        items.each do |item|
-          futures << Concurrent::Future.execute(executor: pool) do
+        futures = items.map do |item|
+          Concurrent::Future.execute(executor: pool) do
             if !progress.total.nil? && progress.progress + 1 > progress.total
               # The number of items has changed between start and now,
               # since there is no good way to predict the final count from