Revert "JAVA-20280: remove wrong property (#13874)" (#14021)

This reverts commit 58d9bcb3b4.

spring-reactive-modules/spring-reactive-exceptions/src/main/resources/application.yaml

@@ -1,3 +1,7 @@
+spring:
+  codec:
+    max-in-memory-size: 500KB
+
 server:
   port: 8080
 host: http://localhost:${server.port}