Refine CDS how-to guide

As explained in gh-41348, the BP_SPRING_AOT_ENABLED flag should
not be promoted as it can't work by design with our current
support when combined with CDS for various use cases and provides
little added value as the same behavior can be achieved by adding
-Dspring.aot.enabled=true to JAVA_TOOL_OPTIONS and
CDS_TRAINING_JAVA_TOOL_OPTIONS.

See gh-41464

Author: sdeleuze

spring-boot-project/spring-boot-docs/src/docs/antora/modules/how-to/pages/class-data-sharing.adoc

@@ -13,8 +13,6 @@ Spring Boot's xref:reference:packaging/container-images/cloud-native-buildpacks.
 To enable CDS optimization in a generated Docker image, the buildpack environment variable `BP_JVM_CDS_ENABLED` should be set to `true` when building the image as described in the xref:maven-plugin:build-image.adoc#build-image.examples.builder-configuration[Maven plugin] and xref:gradle-plugin:packaging-oci-image.adoc#build-image.examples.builder-configuration[Gradle plugin] documentation.
 This will cause the buildpack to do a training run of the application, save the CDS archive in the image, and use the CDS archive when launching the application.
 
-The buildpack environment variable `BP_SPRING_AOT_ENABLED` can also be set to `true` to enable AOT mode along with CDS when running an application that has been xref:reference:packaging/aot.adoc[built with Ahead-of-Time processed].
-
 The Paketo Buildpack for Spring Boot https://github.com/paketo-buildpacks/spring-boot?tab=readme-ov-file#configuration[documentation] has information on other configuration options that can be enabled with builder environment variables, like `CDS_TRAINING_JAVA_TOOL_OPTIONS` that allows to override the default `JAVA_TOOL_OPTIONS`, only for the CDS training run.
 
 [[howto.class-data-sharing.training-run-configuration]]