Un-finalize IpSecManager

Allows VCN and IKE unit tests to mock IpSecManager and thus stop
depending on the hidden APIs in the Connectivity module
(e.g. IpSecService binder interface). Otherwise, any changes on
these related hidden APIs will require topic changes across multiple
projects.

Ignore-AOSP-First: Avoiding conflicts; cherry-pick will follow
Bug: 217572993
Test: make update-api
Test: atest IpSecManagerTest, IpSecManagerTunnelTest
Change-Id: I417e243d9d2650e3d977a9e2bb70824652ccbf28
diff --git a/framework-t/api/system-current.txt b/framework-t/api/system-current.txt
index c5cb98c..492d5a5 100644
--- a/framework-t/api/system-current.txt
+++ b/framework-t/api/system-current.txt
@@ -326,7 +326,7 @@
 
 package android.net {
 
-  public final class IpSecManager {
+  public class IpSecManager {
     method @RequiresPermission(android.Manifest.permission.MANAGE_IPSEC_TUNNELS) public void applyTunnelModeTransform(@NonNull android.net.IpSecManager.IpSecTunnelInterface, int, @NonNull android.net.IpSecTransform) throws java.io.IOException;
     method @NonNull @RequiresPermission(android.Manifest.permission.MANAGE_IPSEC_TUNNELS) public android.net.IpSecManager.IpSecTunnelInterface createIpSecTunnelInterface(@NonNull java.net.InetAddress, @NonNull java.net.InetAddress, @NonNull android.net.Network) throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException;
   }