Fix settings test for show_notification_channel_warnings

Test: runtest --path
core/tests/coretests/src/android/provider/SettingsBackupTesst.jav
Bug: 37684646

Change-Id: I77ff42107979b22ca2d4b81a406fc69a5b16417f
diff --git a/core/tests/coretests/src/android/provider/SettingsBackupTest.java b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
index aeed20e..4a2e884 100644
--- a/core/tests/coretests/src/android/provider/SettingsBackupTest.java
+++ b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
@@ -308,6 +308,7 @@
                     Settings.Global.SETUP_PREPAID_DETECTION_REDIR_HOST,
                     Settings.Global.SETUP_PREPAID_DETECTION_TARGET_URL,
                     Settings.Global.SHORTCUT_MANAGER_CONSTANTS,
+                    Settings.Global.SHOW_NOTIFICATION_CHANNEL_WARNINGS,
                     Settings.Global.SHOW_TEMPERATURE_WARNING,
                     Settings.Global.SMART_SELECTION_UPDATE_CONTENT_URL,
                     Settings.Global.SMART_SELECTION_UPDATE_METADATA_URL,