Create Settings.Global.ENABLE_SMART_REPLIES_IN_NOTIFICATIONS setting

This will allow us to toggle and experiment with the feature.

Bug: 67765414
Test: atest SettingsBackupTest
Change-Id: I28d0a817561cb6811966d229e8367adb4eb6d40b
diff --git a/core/tests/coretests/src/android/provider/SettingsBackupTest.java b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
index 410bee0..c29d79c 100644
--- a/core/tests/coretests/src/android/provider/SettingsBackupTest.java
+++ b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
@@ -204,6 +204,7 @@
                     Settings.Global.ENABLE_DELETION_HELPER_NO_THRESHOLD_TOGGLE,
                     Settings.Global.ENABLE_DISKSTATS_LOGGING,
                     Settings.Global.ENABLE_EPHEMERAL_FEATURE,
+                    Settings.Global.ENABLE_SMART_REPLIES_IN_NOTIFICATIONS,
                     Settings.Global.ENHANCED_4G_MODE_ENABLED,
                     Settings.Global.EPHEMERAL_COOKIE_MAX_SIZE_BYTES,
                     Settings.Global.ERROR_LOGCAT_PREFIX,