Add feature flag for settings slice injection

Bug: 120803703
Test: Manual
Change-Id: If5ff1fc867d010953a5aa48b2ba61a4c467b6579
diff --git a/src/com/android/settings/core/FeatureFlags.java b/src/com/android/settings/core/FeatureFlags.java
index b350778..7f14c0d 100644
--- a/src/com/android/settings/core/FeatureFlags.java
+++ b/src/com/android/settings/core/FeatureFlags.java
@@ -27,4 +27,5 @@
     public static final String WIFI_MAC_RANDOMIZATION = "settings_wifi_mac_randomization";
     public static final String NETWORK_INTERNET_V2 = "settings_network_and_internet_v2";
     public static final String WIFI_SHARING = "settings_wifi_sharing";
+    public static final String SLICE_INJECTION = "settings_slice_injection";
 }