Nit, ifrt_proxy: Remove declaration of unused HandleReshardRequest() function.

PiperOrigin-RevId: 736927658

Author: Google-ML-Automation

xla/python/ifrt_proxy/server/ifrt_backend.h

@@ -149,8 +149,6 @@ class IfrtBackend final : public BackendInterface {
       std::unique_ptr<IfrtRequest> request);
   absl::StatusOr<Response> HandleCopyArraysRequest(
       std::unique_ptr<IfrtRequest> request);
-  absl::StatusOr<Response> HandleReshardRequest(
-      std::unique_ptr<IfrtRequest> request);
   absl::StatusOr<Response> HandleFullyReplicatedShardRequest(
       std::unique_ptr<IfrtRequest> request);
   absl::StatusOr<Response> HandleDeleteArrayRequest(