[Thread] remove OT_ERROR_DETACHED

remove handling of this error code given it's not returned from
IOtDaemon APIs.

Test: atest CtsThreadNetworkTestCases
Change-Id: Id1d9b9d0ad45b7242e7c1d081b05ac51cf928603
diff --git a/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java b/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
index a16aed6..45b0a74 100644
--- a/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
+++ b/thread/service/java/com/android/server/thread/ThreadNetworkControllerService.java
@@ -45,7 +45,6 @@
 
 import static com.android.server.thread.openthread.IOtDaemon.ErrorCode.OT_ERROR_ABORT;
 import static com.android.server.thread.openthread.IOtDaemon.ErrorCode.OT_ERROR_BUSY;
-import static com.android.server.thread.openthread.IOtDaemon.ErrorCode.OT_ERROR_DETACHED;
 import static com.android.server.thread.openthread.IOtDaemon.ErrorCode.OT_ERROR_FAILED_PRECONDITION;
 import static com.android.server.thread.openthread.IOtDaemon.ErrorCode.OT_ERROR_INVALID_STATE;
 import static com.android.server.thread.openthread.IOtDaemon.ErrorCode.OT_ERROR_NO_BUFS;
@@ -672,7 +671,6 @@
                 return ERROR_THREAD_DISABLED;
             case OT_ERROR_FAILED_PRECONDITION:
                 return ERROR_FAILED_PRECONDITION;
-            case OT_ERROR_DETACHED:
             case OT_ERROR_INVALID_STATE:
             default:
                 return ERROR_INTERNAL_ERROR;