[Thread] make the Manager and Controller class 'final'

Per the API review council, the classes should be "final" by default

Bug: 301076593
Test: build && atest CtsThreadNetworkTestCases
Change-Id: I85f0b4fabe5b1bcec2be052620b38a07c58181d7
diff --git a/framework-t/api/system-current.txt b/framework-t/api/system-current.txt
index 6c98a4f..23510e1 100644
--- a/framework-t/api/system-current.txt
+++ b/framework-t/api/system-current.txt
@@ -492,12 +492,12 @@
     field @NonNull public static final android.os.Parcelable.Creator<android.net.thread.PendingOperationalDataset> CREATOR;
   }
 
-  @FlaggedApi("com.android.net.thread.flags.thread_enabled") public class ThreadNetworkController {
+  @FlaggedApi("com.android.net.thread.flags.thread_enabled") public final class ThreadNetworkController {
     method public int getThreadVersion();
     field public static final int THREAD_VERSION_1_3 = 4; // 0x4
   }
 
-  @FlaggedApi("com.android.net.thread.flags.thread_enabled") public class ThreadNetworkManager {
+  @FlaggedApi("com.android.net.thread.flags.thread_enabled") public final class ThreadNetworkManager {
     method @NonNull public java.util.List<android.net.thread.ThreadNetworkController> getAllThreadNetworkControllers();
   }
 
diff --git a/thread/framework/java/android/net/thread/ThreadNetworkController.java b/thread/framework/java/android/net/thread/ThreadNetworkController.java
index 9db8132..7575757 100644
--- a/thread/framework/java/android/net/thread/ThreadNetworkController.java
+++ b/thread/framework/java/android/net/thread/ThreadNetworkController.java
@@ -34,7 +34,7 @@
 */
 @FlaggedApi(ThreadNetworkFlags.FLAG_THREAD_ENABLED)
 @SystemApi
-public class ThreadNetworkController {
+public final class ThreadNetworkController {
 
     /** Thread standard version 1.3. */
     public static final int THREAD_VERSION_1_3 = 4;
diff --git a/thread/framework/java/android/net/thread/ThreadNetworkManager.java b/thread/framework/java/android/net/thread/ThreadNetworkManager.java
index 3e8288c..c3bdbd7 100644
--- a/thread/framework/java/android/net/thread/ThreadNetworkManager.java
+++ b/thread/framework/java/android/net/thread/ThreadNetworkManager.java
@@ -38,7 +38,7 @@
 @FlaggedApi(ThreadNetworkFlags.FLAG_THREAD_ENABLED)
 @SystemApi
 @SystemService(ThreadNetworkManager.SERVICE_NAME)
-public class ThreadNetworkManager {
+public final class ThreadNetworkManager {
     /**
      * This value tracks {@link Context#THREAD_NETWORK_SERVICE}.
      *