Fix testDataDisconnectedNotification unit test.

Also, increment wait time to 300.

Change-Id: I00921cd292dc15d0326750b547f302c94a33481a
Test: ran unit test manually.
Fix: 63592070
diff --git a/src/com/android/phone/NotificationMgr.java b/src/com/android/phone/NotificationMgr.java
index 61bf860..9a90f5b 100644
--- a/src/com/android/phone/NotificationMgr.java
+++ b/src/com/android/phone/NotificationMgr.java
@@ -50,7 +50,6 @@
 import android.util.Log;
 import android.widget.Toast;
 
-import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.telephony.Phone;
 import com.android.internal.telephony.PhoneFactory;
 import com.android.internal.telephony.TelephonyCapabilities;
@@ -544,8 +543,7 @@
      * appears when you lose data connectivity because you're roaming and
      * you have the "data roaming" feature turned off.
      */
-    @VisibleForTesting
-    public void showDataDisconnectedRoaming() {
+    void showDataDisconnectedRoaming() {
         if (DBG) log("showDataDisconnectedRoaming()...");
 
         // "Mobile network settings" screen / dialog