Provide default codecs config callback to custom codecs #24118
Description
As of #23961, developers can now configure ExchangeStrategies and the underlying codec infrastructure without overriding other preferences. Some of those preferences, like limit on buffer sizes and logging request details are only applied to default codecs, as custom codecs might have different opinions.
We now need to let custom codecs know about those opinions set on the defaults, otherwise they would have no chance to align there if they wanted to.