Flag activities for bubbles shortcut

Put activities behind a flag in the manifest.

Bug: 340337839
Flag: com.android.wm.shell.enable_retrievable_bubbles
Test: m droid
Change-Id: I8256e9daac8d0071173e44d52de499e2acd70211
diff --git a/libs/WindowManager/Shell/Android.bp b/libs/WindowManager/Shell/Android.bp
index e6cb3a0..5135e9e 100644
--- a/libs/WindowManager/Shell/Android.bp
+++ b/libs/WindowManager/Shell/Android.bp
@@ -239,6 +239,9 @@
         "wmshell.protolog.json.gz",
         "wmshell.protolog.pb",
     ],
+    flags_packages: [
+        "com_android_wm_shell_flags",
+    ],
     kotlincflags: ["-Xjvm-default=all"],
     manifest: "AndroidManifest.xml",
     plugins: ["dagger2-compiler"],