Do not timeout private DNS before NetworkMonitor

NetworkMonitor uses 10+s timeout for various phases of validation (12.5s
by default for DNS probes, 10s for HTTP/HTTPS probes and private DNS
probe). Having a 10s timeout for the private DNS setting may fail tests
while NetworkMonitor is still considering it acceptable.

Increase the timeout to 30s, which matches the timeout used in
ConnectUtil to wait for NetworkMonitor validation (ensureWifiValidated).

Test: atest
Change-Id: I084f85f25a26fc8417fdb566e75e49f427391a98
diff --git a/tests/cts/net/util/java/android/net/cts/util/CtsNetUtils.java b/tests/cts/net/util/java/android/net/cts/util/CtsNetUtils.java
index 670889f..0dd2a23 100644
--- a/tests/cts/net/util/java/android/net/cts/util/CtsNetUtils.java
+++ b/tests/cts/net/util/java/android/net/cts/util/CtsNetUtils.java
@@ -93,7 +93,7 @@
     private static final int SOCKET_TIMEOUT_MS = 10_000;
     private static final int PRIVATE_DNS_PROBE_MS = 1_000;
 
-    private static final int PRIVATE_DNS_SETTING_TIMEOUT_MS = 10_000;
+    private static final int PRIVATE_DNS_SETTING_TIMEOUT_MS = 30_000;
     private static final int CONNECTIVITY_CHANGE_TIMEOUT_SECS = 30;
 
     private static final String PRIVATE_DNS_MODE_OPPORTUNISTIC = "opportunistic";