the codec Delegator class is incomplete and does not support the === operator #11434
Description
Followup of #11140
Starting in 7.2.0 codecs were wrapped in a delegator:
https://github.com/elastic/logstash/blob/v7.2.0/logstash-core/lib/logstash/config/mixin.rb#L414
https://github.com/elastic/logstash/blob/v7.2.0/logstash-core/lib/logstash/codecs/delegator.rb
but this Delegator class does not redefine the === operator which is used by the case/when statement on classes.
It broke the fix_streaming_codec and this problem was solved by avoiding testing on the class in #11401 but I believe we should also fix the root cause to avoid any further potential related problems by fixing or changing the codec delegator.