Fix statsd UDP sockets not being cleaned up in Sidekiq (mastodon#11230)

Author: Gargron

app/lib/sidekiq_error_handler.rb

@@ -3,9 +3,11 @@
 class SidekiqErrorHandler
   def call(*)
     yield
-  rescue Mastodon::HostValidationError => e
-    Rails.logger.error "#{e.class}: #{e.message}"
-    Rails.logger.error e.backtrace.join("\n")
+  rescue Mastodon::HostValidationError
     # Do not retry
+  ensure
+    socket = Thread.current[:statsd_socket]
+    socket&.close
+    Thread.current[:statsd_socket] = nil
   end
 end