EPCtx changes for dynamic model with reshape_input provider optional

1. Throw an ErrorMessage when user provide reshape_input with EPctx graph.
2. Do not Create dynamic_backend for EPctx graph.

Update onnxruntime/core/providers/openvino/backend_manager.cc

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: gupta-pallavi

onnxruntime/core/providers/openvino/backend_manager.cc

@@ -84,6 +84,11 @@ BackendManager::BackendManager(SessionContext& session_context,
   ptr_stream_t model_stream;
   std::unique_ptr<onnx::ModelProto> model_proto;
   if (subgraph_context_.is_ep_ctx_graph) {
+    if (!session_context_.reshape.empty()) {
+      std::string exception_str =
+          "[OpenVINO-EP] reshape_input is not supported for EPContext graph";
+      ORT_THROW(exception_str);
+    }
     model_stream = ep_ctx_handle_.GetModelBlobStream(session_context_.so_context_file_path, subgraph);
   } else {
     model_proto = GetModelProtoFromFusedNode(fused_node, subgraph, logger);
@@ -125,6 +130,21 @@ BackendManager::BackendManager(SessionContext& session_context,
       LOGS_DEFAULT(INFO) << "[OpenVINO-EP] "
                          << "Backend created for graph " << subgraph_context_.subgraph_name;
     } else {
+        // Do not create dynamic backend for EPCtx graph
+      if (subgraph_context_.is_ep_ctx_graph) {
+        LOGS_DEFAULT(INFO) << "[OpenVINO-EP] Starting backend initialization. "
+                           << "Initializing backend for EPContext graph "
+                           << subgraph_context_.subgraph_name;
+        try {
+          concrete_backend_ = BackendFactory::MakeBackend(model_proto,
+                                                          session_context_,
+                                                          subgraph_context_,
+                                                          shared_context_,
+                                                          model_stream);
+        } catch (std::string const& msg) {
+          ORT_THROW(msg);
+        }
+      }
       // Only cache model_proto in session context to rewrite the model with input shapes at runtime.
       // For dynamic backend creation
       model_proto_ = std::move(model_proto);
@@ -590,7 +610,7 @@ void BackendManager::Compute(OrtKernelContext* context) {
   // by rewriting the model to static shaped model at runtime based on input shape.
   // disable_dynamic_shapes should be set for devices that don't support dynamic shapes.
   bool need_dynamic_backend = subgraph_context_.has_dynamic_input_shape &&
-                              session_context_.disable_dynamic_shapes;
+                              session_context_.disable_dynamic_shapes && !subgraph_context_.is_ep_ctx_graph;
 
   if (!need_dynamic_backend) {
     concrete_backend_->Infer(context);