GH-STREAM 2704 Fix Consumer CCE on Kotlin Consumer

Resolves #2704

Author: olegz

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/KotlinLambdaToFunctionAutoConfiguration.java

@@ -123,7 +123,11 @@ public Object invoke(Object arg0) {
 			if (this.kotlinLambdaTarget instanceof Function1) {
 				return ((Function1) this.kotlinLambdaTarget).invoke(arg0);
 			}
-			return ((Function) this.kotlinLambdaTarget).apply(arg0);
+			else if (this.kotlinLambdaTarget instanceof Function) {
+				return ((Function) this.kotlinLambdaTarget).apply(arg0);
+			}
+			((Consumer) this.kotlinLambdaTarget).accept(arg0);
+			return null;
 		}
 
 		@Override