Add aconfig flag for x on mouse hover for notifications

This will allow us to do a gantry rollout for the new
X which will show on mouse hover on all individual notifications.

Flag: NONE just adding the aconfig flag
Test: NONE (same reasoning)
Change-Id: I9292485f1b309ad1af1b0f37b0817c3f4e2fe4e7
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index d124c02..3a9421f 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -59,7 +59,7 @@
 flag {
    name: "notification_over_expansion_clipping_fix"
    namespace: "systemui"
-   description: "fix NSSL clipping when over-expanding; fixes split shade bug."
+   description: "Fix NSSL clipping when over-expanding; fixes split shade bug."
    bug: "288553572"
    metadata {
         purpose: PURPOSE_BUGFIX
@@ -67,6 +67,14 @@
 }
 
 flag {
+    name: "notification_add_x_on_hover_to_dismiss"
+    namespace: "systemui"
+    description: "Adds an x to notifications which shows up on mouse hover, allowing the user to "
+        "dismiss a notification with mouse."
+    bug: "376297472"
+}
+
+flag {
     name: "notification_async_group_header_inflation"
     namespace: "systemui"
     description: "Inflates the notification group summary header views from the background thread."