Add note about `@[Enabled|Disabled]InNativeImage` in reference manual

[sbrannen]

Overview

Although @EnabledInNativeImage and @DisabledInNativeImage are part of JUnit Jupiter, many Spring users don't realize that those annotations/conditions are available for use with Spring integration tests running in a GraalVM native image.

We should therefore add a note about them in the new documentation for @DisabledInAotMode.

Related Issues

• Introduce @DisabledInAotMode in the TestContext framework #30834
• Document @DisabledInAotMode in the reference manual #31437
• How can I exclude test classes when running nativeTest? (Stack Overflow)