build: Suppress obsolete Java 8 option warning under JDK 21+ (#5664)

The root build compiles Java with -Xlint:all -Werror. On JDK 21+,
javac flags -source/-target 8 as obsolete, and -Werror promotes that
warning to an error, failing :sentry:compileJava. CI pins JDK 17,
where the warning does not exist, so this only breaks local builds and
tooling on newer JDKs (e.g. the Kotlin LSP's bundled JDK 25, whose
Gradle project import aborts and loses cross-module resolution).

Add -Xlint:-options, the suppression javac itself recommends when
intentionally targeting an older release.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: runningcode

build.gradle.kts

@@ -105,7 +105,7 @@ allprojects {
             )
         }
         withType<JavaCompile>().configureEach {
-            options.compilerArgs.addAll(arrayOf("-Xlint:all", "-Werror", "-Xlint:-classfile", "-Xlint:-processing", "-Xlint:-try"))
+            options.compilerArgs.addAll(arrayOf("-Xlint:all", "-Werror", "-Xlint:-classfile", "-Xlint:-processing", "-Xlint:-try", "-Xlint:-options"))
         }
     }
 }