Add aconfig flag for enabling the "mute volume" contextual tip

Bug: 337737048
Change-Id: I81fe075a2e91e0aa64b8ca622eb8452a64eed436
Test: NONE this just adds the flag. No change in behavior yet.
Flag: ACONFIG com.android.systemui.enable_contextual_tip_for_mute_volume DEVELOPMENT
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index 21881f6..80398cd 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -550,6 +550,13 @@
 }
 
 flag {
+    name: "enable_contextual_tip_for_mute_volume"
+    namespace: "systemui"
+    description: "Enables the contextual tip for muting the volume."
+    bug: "337737048"
+}
+
+flag {
    name: "disable_contextual_tips_frequency_check"
    description: "Disables frequency capping check for contextual tips."
    namespace: "systemui"