Adding linter for checking license (and copyright)  header in java/kotlin files

Fixes: 302679200
Test: MissingApacheLicenseDetectorTest
Test: run `m SYSTEM_UI_CORE_PATH/lint-report.html` and see legit license warnings/errors
Change-Id: I8c79e74f6a171964b30b93e029eeef0ef72a045c
diff --git a/packages/SystemUI/Android.bp b/packages/SystemUI/Android.bp
index ee05f2d..0284117 100644
--- a/packages/SystemUI/Android.bp
+++ b/packages/SystemUI/Android.bp
@@ -212,6 +212,7 @@
 
     lint: {
         extra_check_modules: ["SystemUILintChecker"],
+        warning_checks: ["MissingApacheLicenseDetector"],
     },
 }