Update javadocs for ConnectivityDiagnosticsManager.

ConnectivityDiagnosticsManager comments for
registerConnectivityDiagnosticsCallback and
unregisterConnectivityDiagnosticsCallback are updated to reflect several
changes.

For register calls, any app will be able to register callbacks, but only
permissioned applications will have their callbacks invoked (and only
for networks managed by the application). Additionally, only the
registering app (uid) will be able to unregister a callback once
registered.

Bug: 143187964
Test: docs change only. compiles.
Change-Id: Ie7ae86a1afccb22d6c84027dbac49d7b8e431e8c
diff --git a/core/java/android/net/ConnectivityDiagnosticsManager.java b/core/java/android/net/ConnectivityDiagnosticsManager.java
index d018cbd..140363c 100644
--- a/core/java/android/net/ConnectivityDiagnosticsManager.java
+++ b/core/java/android/net/ConnectivityDiagnosticsManager.java
@@ -639,8 +639,9 @@
     /**
      * Registers a ConnectivityDiagnosticsCallback with the System.
      *
-     * <p>Only apps that offer network connectivity to the user are allowed to register callbacks.
-     * This includes:
+     * <p>Only apps that offer network connectivity to the user should be registering callbacks.
+     * These are the only apps whose callbacks will be invoked by the system. Apps considered to
+     * meet these conditions include:
      *
      * <ul>
      *   <li>Carrier apps with active subscriptions
@@ -648,8 +649,7 @@
      *   <li>WiFi Suggesters
      * </ul>
      *
-     * <p>Callbacks will be limited to receiving notifications for networks over which apps provide
-     * connectivity.
+     * <p>Callbacks registered by apps not meeting the above criteria will not be invoked.
      *
      * <p>If a registering app loses its relevant permissions, any callbacks it registered will
      * silently stop receiving callbacks.