Add Stub version of PluginProtector

Bug: 359432141
Test: test_gradle_build.sh
TesT: m SystemUIGoogle
Flag: NONE Build changes
Change-Id: I1faf3f7e4345733b18ee521302b310f92793e6a4
diff --git a/packages/SystemUI/plugin/Android.bp b/packages/SystemUI/plugin/Android.bp
index a26cf12..6212e2b 100644
--- a/packages/SystemUI/plugin/Android.bp
+++ b/packages/SystemUI/plugin/Android.bp
@@ -30,6 +30,9 @@
         "src/**/*.java",
         "src/**/*.kt",
     ],
+    exclude_srcs: [
+        "src/**/PluginProtectorStub.kt",
+    ],
 
     optimize: {
         proguard_flags_files: [