Drop jackson-module-kotlin from spring-boot-starter-json

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

spring-boot-project/spring-boot-starters/spring-boot-starter-json/pom.xml

@@ -37,15 +37,5 @@
 			<groupId>com.fasterxml.jackson.module</groupId>
 			<artifactId>jackson-module-parameter-names</artifactId>
 		</dependency>
-		<dependency>
-			<groupId>com.fasterxml.jackson.module</groupId>
-			<artifactId>jackson-module-kotlin</artifactId>
-			<exclusions>
-				<exclusion>
-					<groupId>org.jetbrains.kotlin</groupId>
-					<artifactId>kotlin-reflect</artifactId>
-				</exclusion>
-			</exclusions>
-		</dependency>
 	</dependencies>
 </project>