aconfig: include namespace in create-device-config-defaults

Update the output format of create-device-config-defaults to include the
flag's namespace. Also change the delimiters. The new format is

  <namespace>:<package>.<flag-name>=[enabled|disabled|

Bug: 285468565
Test: atest aconfig.test
Change-Id: I9b4ca1611cca8528dc341fc12812b614c86f6c08
diff --git a/tools/aconfig/src/commands.rs b/tools/aconfig/src/commands.rs
index 8be11cc..586ba04 100644
--- a/tools/aconfig/src/commands.rs
+++ b/tools/aconfig/src/commands.rs
@@ -106,7 +106,8 @@
     for item in sort_and_iter_items(caches).filter(|item| item.permission == Permission::ReadWrite)
     {
         let line = format!(
-            "{}/{}:{}\n",
+            "{}:{}.{}={}\n",
+            item.namespace,
             item.package,
             item.name,
             match item.state {
@@ -248,7 +249,7 @@
         let caches = vec![crate::test::create_cache()];
         let bytes = create_device_config_defaults(caches).unwrap();
         let text = std::str::from_utf8(&bytes).unwrap();
-        assert_eq!("com.android.aconfig.test/disabled_rw:disabled\ncom.android.aconfig.test/enabled_rw:enabled\n", text);
+        assert_eq!("aconfig_test:com.android.aconfig.test.disabled_rw=disabled\naconfig_test:com.android.aconfig.test.enabled_rw=enabled\n", text);
     }
 
     #[test]