Drop username_hash from ConfirmUsernameResponse

service/src/main/java/org/whispersystems/textsecuregcm/grpc/AccountsGrpcService.java

@@ -235,7 +235,6 @@ public class AccountsGrpcService extends SimpleAccountsGrpc.AccountsImplBase {
 
       return ConfirmUsernameHashResponse.newBuilder()
           .setConfirmedUsernameHash(ConfirmUsernameHashResponse.ConfirmedUsernameHash.newBuilder()
-              .setUsernameHash(ByteString.copyFrom(updatedAccount.getUsernameHash().orElseThrow()))
               .setUsernameLinkHandle(UUIDUtil.toByteString(updatedAccount.getUsernameLinkHandle())))
           .build();
     } catch (final UsernameHashNotAvailableException e) {

service/src/main/proto/org/signal/chat/account.proto

@@ -189,8 +189,7 @@ message ConfirmUsernameHashRequest {
 
 message ConfirmUsernameHashResponse {
   message ConfirmedUsernameHash {
-    // The newly-confirmed username hash.
-    bytes username_hash = 1;
+    reserved 1; // username_hash
 
     // The server-generated username link handle for the newly-confirmed username.
     bytes username_link_handle = 2;

service/src/test/java/org/whispersystems/textsecuregcm/grpc/AccountsGrpcServiceTest.java

@@ -394,7 +394,6 @@ class AccountsGrpcServiceTest extends SimpleBaseGrpcTest<AccountsGrpcService, Ac
 
     final ConfirmUsernameHashResponse expectedResponse = ConfirmUsernameHashResponse.newBuilder()
         .setConfirmedUsernameHash(ConfirmUsernameHashResponse.ConfirmedUsernameHash.newBuilder()
-            .setUsernameHash(ByteString.copyFrom(usernameHash))
             .setUsernameLinkHandle(UUIDUtil.toByteString(linkHandle))
             .build())
         .build();