Spring Security Add Kotlin example for basic WebTestClient Security setup of reactive applications

Describe the bug A basic WebTestClient Security Setup comes with only Java example.

To Reproduce 1. Browse to WebTestClient Security Setup page. 2. A coding block of the basic setup comes with one Java example.

Expected behavior A coding block of a basic WebTestClient Security Setup should come with both of Java and Kotlin examples.

Sample Reference to pages/reactive/test/web/setup.adoc of 5.7.x branch.

Comment From: eleftherias

Thanks for reaching out @talerngpong! This is a duplicate of #9998.

The issue #9998 was previously blocked, but it looks like it could work now on the main Spring Security branch (which uses Spring Framework 6).

Feel free to submit a PR referencing #9998.

If you do choose to submit a PR for the documentation, please test the code in a sample application. We wouldn't want to have code in our documentation that doesn't work!