Prior to this commit, references to `JsonGenerator` and
`ByteArrayBuilder` were not closed/released within codecs calls.
This prevents Jackson from reusing more efficiently shared memory
resources.
This commit properly closes/releases Jackson resources in Spring MVC,
Spring WebFlux and Spring Messaging codecs.
A benchmark on WebFlux codecs (in both single value/streaming mode)
shows significant throughput and allocation improvements for small
payloads.
Closes gh-25910
7bee3d1574