Previously, a dependency on jackson-module-kotlin with Kotlin excluded
was added to spring-boot-starter-json. This gave Kotlin users a smooth
experience with Jackson and JSON at minimal, we thought, cost to other
users. We have since learned that this arrangement causes a
ClassNotFoundException at runtime when Jackson is configured to find
modules via the service loader. This makes the cost of including
jackson-module-kotlin to high for non-Kotlin users so this commit
removes it.

Closes gh-11133