Add VpnTest back to presubmut

These tests were disabled from presubmit because of flaky test.
It's no longer flaky now, so add these tests back to presubmit.

Bug: 293233390
Test: atest FrameworksNetTests
Change-Id: I7f1f36385d2ca6ed210e1d9b7399b6509fd26519
diff --git a/tests/unit/java/com/android/server/connectivity/VpnTest.java b/tests/unit/java/com/android/server/connectivity/VpnTest.java
index ad178c0..385f831 100644
--- a/tests/unit/java/com/android/server/connectivity/VpnTest.java
+++ b/tests/unit/java/com/android/server/connectivity/VpnTest.java
@@ -182,7 +182,6 @@
 import com.android.server.VpnTestBase;
 import com.android.server.vcn.util.PersistableBundleUtils;
 import com.android.testutils.DevSdkIgnoreRule;
-import com.android.testutils.SkipPresubmit;
 
 import org.junit.Before;
 import org.junit.Rule;
@@ -1712,7 +1711,6 @@
                 errorCode);
     }
 
-    @SkipPresubmit(reason = "Out of SLO flakiness")
     @Test
     public void testStartPlatformVpnFailedWithRecoverableError() throws Exception {
         final IkeProtocolException exception = mock(IkeProtocolException.class);
@@ -1722,7 +1720,6 @@
                 VpnManager.CATEGORY_EVENT_IKE_ERROR, VpnManager.ERROR_CLASS_RECOVERABLE, errorCode);
     }
 
-    @SkipPresubmit(reason = "Out of SLO flakiness")
     @Test
     public void testStartPlatformVpnFailedWithUnknownHostException() throws Exception {
         final IkeNonProtocolException exception = mock(IkeNonProtocolException.class);
@@ -1734,7 +1731,6 @@
                 errorCode);
     }
 
-    @SkipPresubmit(reason = "Out of SLO flakiness")
     @Test
     public void testStartPlatformVpnFailedWithIkeTimeoutException() throws Exception {
         final IkeNonProtocolException exception = mock(IkeNonProtocolException.class);
@@ -1756,7 +1752,6 @@
                 VpnManager.ERROR_CODE_NETWORK_LOST);
     }
 
-    @SkipPresubmit(reason = "Out of SLO flakiness")
     @Test
     public void testStartPlatformVpnFailedWithIOException() throws Exception {
         final IkeNonProtocolException exception = mock(IkeNonProtocolException.class);
@@ -2389,7 +2384,6 @@
                 true /* areLongLivedTcpConnectionsExpensive */);
     }
 
-    @SkipPresubmit(reason = "Out of SLO flakiness")
     @Test
     public void testPreferredIpProtocolFromCarrierConfig_v4UDP() throws Exception {
         doTestReadCarrierConfig(createTestCellNc(),
@@ -2402,7 +2396,6 @@
                 false /* areLongLivedTcpConnectionsExpensive */);
     }
 
-    @SkipPresubmit(reason = "Out of SLO flakiness")
     @Test
     public void testPreferredIpProtocolFromCarrierConfig_v6ESP() throws Exception {
         doTestReadCarrierConfig(createTestCellNc(),
@@ -2415,7 +2408,6 @@
                 false /* areLongLivedTcpConnectionsExpensive */);
     }
 
-    @SkipPresubmit(reason = "Out of SLO flakiness")
     @Test
     public void testPreferredIpProtocolFromCarrierConfig_v6UDP() throws Exception {
         doTestReadCarrierConfig(createTestCellNc(),