Added missing method of logger wrapper for puma (#15640)

This commit fixes no method error when node stats API got
invalid API path, which triggers puma to print error using stderr

Fix: #15639

logstash-core/lib/logstash/patches/puma.rb

@@ -126,6 +126,10 @@ def unknown_error(error, req = nil, text = "Unknown error")
     def debug_error(error, req = nil, text = "")
       @logger.debug(text, { error: error, req: req, backtrace: error&.backtrace }) if @logger.debug?
     end
+
+    def debug?
+      @logger.debug?
+    end
   end
 end