Wifi: Add notification ID for softap auto shutdown

Notify the user that their softap disabled because there are no connected
devices and shutdown timeout expired.

Bug: 142752869
Test:  atest FrameworksWifiTests
Change-Id: Ib68607c1fcdced280191af397eda3cc900bdf7cf
diff --git a/proto/src/system_messages.proto b/proto/src/system_messages.proto
index 21100458ad..ad802ff 100644
--- a/proto/src/system_messages.proto
+++ b/proto/src/system_messages.proto
@@ -240,6 +240,10 @@
     // Inform the user that EAP failure occurs
     NOTE_WIFI_EAP_FAILURE = 57;
 
+    // Notify the user that their softap disabled because auto shutdown timeout expired.
+    // Package: android
+    NOTE_SOFTAP_AUTO_DISABLED = 58;
+
     // ADD_NEW_IDS_ABOVE_THIS_LINE
     // Legacy IDs with arbitrary values appear below
     // Legacy IDs existed as stable non-conflicting constants prior to the O release