ConnectivityManagerTest: clean up when connectToCell fails

CtsNetUtils#connectToCell can fail if the device does not have a cell
network available in which case the allow bad wifi setting was not reset.

Test: TH
Change-Id: I2dc20c8982a427379f94a4b92774e149a78628d5
diff --git a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
index 423b2bd..4cc5276 100644
--- a/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/ConnectivityManagerTest.java
@@ -2960,13 +2960,13 @@
 
         allowBadWifi();
 
-        final Network cellNetwork = mCtsNetUtils.connectToCell();
-        final Network wifiNetwork = prepareValidatedNetwork();
-
-        registerDefaultNetworkCallback(defaultCb);
-        registerNetworkCallback(makeWifiNetworkRequest(), wifiCb);
-
         try {
+            final Network cellNetwork = mCtsNetUtils.connectToCell();
+            final Network wifiNetwork = prepareValidatedNetwork();
+
+            registerDefaultNetworkCallback(defaultCb);
+            registerNetworkCallback(makeWifiNetworkRequest(), wifiCb);
+
             // Verify wifi is the default network.
             defaultCb.eventuallyExpect(CallbackEntry.AVAILABLE, NETWORK_CALLBACK_TIMEOUT_MS,
                     entry -> wifiNetwork.equals(entry.getNetwork()));