SpringBoot ArchitectureCheck tasks aren't registered in our Gradle build

When org.springframework.boot.build.architecture.ArchitecturePlugin#registerTasks is called, javaPluginExtension.getSourceSets() is empty.

This can be fixed by reacting to the JavaPlugin instead of JavaBasePlugin.

Comment From: mhalbritter

The upgrade to Gradle 8.10 changed something.

In 7.4 the tasks are there: https://ge.spring.io/s/l5v4knock2np4/timeline?name=architecture

In 8.10 the tasks are gone (same day, different Gradle): https://ge.spring.io/s/3xr57diuxwzci/timeline?name=architecture

Thanks @wilkinsona for digging!