Upgrade to AspectJ 1.9.23

[sbrannen]

AspectJ 1.9.23 has been released with support for JDK 23.

[sbrannen]

To test AspectJ 1.9.23, I ran full builds on Java 21 and Java 23.

Additionally, I ran a build on Java 23 with the source and target compatibility for both compileAspectj and compileTestAspectj in spring-aspects.gradle set to 23, and everything passed.

So, hopefully that indicates proper support for Java 23 with AspectJ 1.9.23.

[sbrannen]

This has been effectively superseded by:

• Upgrade to AspectJ 1.9.24 #34752