supplicant(interface): Add missing STA callbacks

Add a few missing callbacks in ISupplicantStaIfaceCallbacks &
ISupplicantCallbacks.

Bug: 34274091
Test: Compiles
Change-Id: I5d7819f9708f6caa4da80ed481408e376a5636f8
diff --git a/wifi/supplicant/1.0/ISupplicantCallback.hal b/wifi/supplicant/1.0/ISupplicantCallback.hal
index a5a0da5..3674cfb 100644
--- a/wifi/supplicant/1.0/ISupplicantCallback.hal
+++ b/wifi/supplicant/1.0/ISupplicantCallback.hal
@@ -37,4 +37,9 @@
    * @param ifName Name of the network interface, e.g., wlan0
    */
   oneway onInterfaceRemoved(string ifName);
+
+  /**
+   * Used to indicate that the supplicant daemon is terminating.
+   */
+  oneway onTerminating();
 };