This is a follow-up to #742.
The `mcp-test`, `mcp-spring-webflux`, and `mcp-spring-webmvc` depended
on `mcp` module which transitively brought in Jackson 3 dependencies.
These modules are now decoupled and only depend on `mcp-core`.
The test dependencies bring in Jackson 2 for the time being.
This is a breaking change but it is required to allow easily exchanging
Jackson2 and Jackson3 modules.
Signed-off-by: Dariusz Jędrzejczyk <dariusz.jedrzejczyk@broadcom.com>