Make `@JsonUnwrapped` compatible with `@JsonSerialize(converter=)`

[manuel-hegner]

Is your feature request related to a problem? Please describe.

Currently those two are not compatible, because StdConvertingSerializer is not isUnwrappingSerializer. This is especially sad because @JsonUnwrapped is compatible with @JsonSerializer(converter=).

Describe the solution you'd like

StdConvertingSerializer should be unwrapping if its _delegateSerializer is unwrapping. This would allow for the annotation combination to work, if the Converter produces a POJO

Usage example

No response

Additional context

No response

[cowtowncoder]

Fixed as suggested; will be in 3.2.0.