Fix actuator dependency on Jackson JSR 310 module

This commit harmonizes dependency declarations for Jackson in the
actuator. Both Jackson and JSR 310 are back to optional in the core
actuator module and mandatory when using the auto-configuration.

Closes gh-22624

Author: snicoll

spring-boot-project/spring-boot-actuator-autoconfigure/pom.xml

@@ -35,6 +35,10 @@
 			<groupId>com.fasterxml.jackson.core</groupId>
 			<artifactId>jackson-databind</artifactId>
 		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.datatype</groupId>
+			<artifactId>jackson-datatype-jsr310</artifactId>
+		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-core</artifactId>

spring-boot-project/spring-boot-actuator/pom.xml

@@ -26,16 +26,17 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot</artifactId>
 		</dependency>
-		<dependency>
-			<groupId>com.fasterxml.jackson.datatype</groupId>
-			<artifactId>jackson-datatype-jsr310</artifactId>
-		</dependency>
 		<!-- Optional -->
 		<dependency>
 			<groupId>com.fasterxml.jackson.core</groupId>
 			<artifactId>jackson-databind</artifactId>
 			<optional>true</optional>
 		</dependency>
+		<dependency>
+			<groupId>com.fasterxml.jackson.datatype</groupId>
+			<artifactId>jackson-datatype-jsr310</artifactId>
+			<optional>true</optional>
+		</dependency>
 		<dependency>
 			<groupId>com.github.ben-manes.caffeine</groupId>
 			<artifactId>caffeine</artifactId>