Use keep annotations in SystemUI

This is following recommendations from [1].

[1]: go/aperf-keepanno-fixit-faq
Test: manually inspected dexdump http://gpaste/5542863004762112
Bug: 300402748
Change-Id: Ia956da9867ea7303ffa787cdf8771fb09873a878
diff --git a/packages/SystemUI/Android.bp b/packages/SystemUI/Android.bp
index 77925d6..6080101 100644
--- a/packages/SystemUI/Android.bp
+++ b/packages/SystemUI/Android.bp
@@ -203,6 +203,9 @@
         "LowLightDreamLib",
         "motion_tool_lib",
     ],
+    libs: [
+        "keepanno-annotations",
+    ],
     manifest: "AndroidManifest.xml",
 
     javacflags: ["-Adagger.fastInit=enabled"],
@@ -466,6 +469,7 @@
         "android.test.runner",
         "android.test.base",
         "android.test.mock",
+        "keepanno-annotations",
     ],
     kotlincflags: ["-Xjvm-default=all"],
     aaptflags: [
@@ -497,6 +501,9 @@
     static_libs: [
         "SystemUI-tests-base",
     ],
+    libs: [
+        "keepanno-annotations",
+    ],
     aaptflags: [
         "--extra-packages",
         "com.android.systemui",