Fix error within error when limiting backtrace to 3 lines (#13120)

Fix #13086, close #13113

app/lib/sidekiq_error_handler.rb

@@ -1,13 +1,24 @@
 # frozen_string_literal: true
 
 class SidekiqErrorHandler
+  BACKTRACE_LIMIT = 3
+
   def call(*)
     yield
   rescue Mastodon::HostValidationError
     # Do not retry
+  rescue => e
+    limit_backtrace_and_raise(e)
   ensure
     socket = Thread.current[:statsd_socket]
     socket&.close
     Thread.current[:statsd_socket] = nil
   end
+
+  private
+
+  def limit_backtrace_and_raise(e)
+    e.set_backtrace(e.backtrace.first(BACKTRACE_LIMIT))
+    raise e
+  end
 end