Fix logging.group target type

Closes gh-14743

spring-boot-project/spring-boot/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -89,7 +89,7 @@
     },
     {
       "name": "logging.group",
-      "type": "java.util.Map<java.lang.String,java.lang.String>",
+      "type": "java.util.Map<java.lang.String,java.util.List<java.lang.String>>",
       "description": "Log groups to quickly change multiple loggers at the same time. For instance, `logging.level.db=org.hibernate,org.springframework.jdbc`.",
       "sourceType": "org.springframework.boot.context.logging.LoggingApplicationListener"
     },