Use existing `MediaAttachment.remote` scope in media CLI (#28912)

lib/mastodon/cli/media.rb

@@ -58,7 +58,7 @@ module Mastodon::CLI
       end
 
       unless options[:prune_profiles] || options[:remove_headers]
-        processed, aggregate = parallelize_with_progress(MediaAttachment.cached.where.not(remote_url: '').where(created_at: ..time_ago)) do |media_attachment|
+        processed, aggregate = parallelize_with_progress(MediaAttachment.cached.remote.where(created_at: ..time_ago)) do |media_attachment|
           next if media_attachment.file.blank?
 
           size = (media_attachment.file_file_size || 0) + (media_attachment.thumbnail_file_size || 0)