Remove some of the field injections (Sonar recomendtion) (#2218)

Signed-off-by: Avgustin Marinov <Avgustin.Marinov@bosch.com>

hawkbit-security/hawkbit-security-core/src/main/java/org/eclipse/hawkbit/security/MdcHandler.java

@@ -31,6 +31,7 @@ import org.springframework.security.web.access.intercept.AuthorizationFilter;
 import org.springframework.web.filter.OncePerRequestFilter;
 
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
+@SuppressWarnings("java:S6548") // java:S6548 - singleton holder ensures static access to spring resources in some places
 public class MdcHandler {
 
     public static final String MDC_KEY_TENANT = "tenant";
@@ -40,7 +41,6 @@ public class MdcHandler {
 
     @Value("${hawkbit.logging.mdchandler.enabled:true}")
     private boolean mdcEnabled;
-    @Autowired(required = false)
     private SpringSecurityAuditorAware springSecurityAuditorAware = new SpringSecurityAuditorAware();
 
     /**
@@ -50,6 +50,11 @@ public class MdcHandler {
         return SINGLETON;
     }
 
+    @Autowired(required = false) // spring setter injection
+    public void setSpringSecurityAuditorAware(final SpringSecurityAuditorAware springSecurityAuditorAware) {
+        this.springSecurityAuditorAware = springSecurityAuditorAware;
+    }
+
     /**
      * Executes callable and returns the result. If MDC is enabled, it sets the tenant and / or user from the authentication in the MDC context.
      *