Fixes: #9702
Issue link: https://github.com/spring-projects/spring-integration/issues/9702
The current `CheckedCallable.unchecked()` returns `Runnable`, which is not an expectation.
* Deprecate `CheckedCallable.unchecked()` in favor of newly introduced `CheckedCallable.uncheckedCallable()`.
We cannot call it `unchecked()` as well, since `Callable` after erasure becomes similar to class signature as `Runnable`.
(cherry picked from commit 8c22bf6430)