[Server] Patch request without request body causes Null Pointer Exception

[prthakre]

Sample code: https://github.com/Captain-P-Goldfish/SCIM-SDK/tree/1.23.0/samples/scim-sdk-springboot-example

> curl --location --globoff --request PATCH 'http://localhost:8080/scim/v2/Users/c631f2a8-b0d1-4bd8-834f-99ef810555531' -H "Content-Type: application/scim+json"
{
 "detail" : "An internal error has occurred.",
 "schemas" : [ "urn:ietf:params:scim:api:messages:2.0:Error" ],
 "status" : 500
}

Exception thrown by the server:

ERROR de.captaingoldfish.scim.sdk.common.response.ErrorResponse (ErrorResponse.java:58) - jsonNode must not be null
de.captaingoldfish.scim.sdk.common.exceptions.InternalServerException: jsonNode must not be null
	at de.captaingoldfish.scim.sdk.server.endpoints.ResourceEndpointHandler.patchResource(ResourceEndpointHandler.java:1070)
	at de.captaingoldfish.scim.sdk.server.endpoints.ResourceEndpoint.resolveRequest(ResourceEndpoint.java:295)
	at de.captaingoldfish.scim.sdk.server.endpoints.ResourceEndpoint.handleRequest(ResourceEndpoint.java:194)
	at de.captaingoldfish.scim.sdk.server.endpoints.ResourceEndpoint.handleRequest(ResourceEndpoint.java:77)
	at de.captaingoldfish.scim.sdk.springboot.sample.controller.ScimController.handleScimRequest(ScimController.java:68)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
	at java.base/java.lang.reflect.Method.invoke(Method.java:580)