Temporarily downgrade Java compat level for AspectJ classes

AspectJ doesn't support JDK17 language level (yet).
For the time being, this commit is downgrading the language level for
the aspectJ generated classes to 1.8.

Issue gh-10349

aspects/spring-security-aspects.gradle

@@ -1,6 +1,15 @@
 apply plugin: 'io.spring.convention.spring-module'
 apply plugin: 'io.freefair.aspectj'
 
+compileAspectj {
+	sourceCompatibility "1.8"
+	targetCompatibility "1.8"
+}
+compileTestAspectj {
+	sourceCompatibility "1.8"
+	targetCompatibility "1.8"
+}
+
 dependencies {
 	management platform(project(":spring-security-dependencies"))
 	api "org.aspectj:aspectjrt"