onnxruntime

5f94d6c8 - Improve error message when EPContext node is not assigned to an EP (#27474)

Improve error message when EPContext node is not assigned to an EP (#27474) ### Description Improves the error message returned by ORT when loading a compiled model in a session that does not have the required execution provider(s). For example, ORT now returns the following error when creating session with a model compiled explicitly for OpenVINO EP without adding OpenVINO EP to the session: > EPContext node generated by 'OpenVINOExecutionProvider' is not compatible with any execution provider added to the session. EPContext node name: 'EPContextNode0'. Available session execution providers: [CPUExecutionProvider]. Compare the above message with the more generic message that is currently returned: >Could not find an implementation for EPContext(1) node with name 'EPContextNode0' ### Motivation and Context Improves diagnosability when loading of pre-compiled models fails. Specifically, the ambiguity of the original message led to many hours spent debugging an error where a compiled model failed to run because the expected `OrtEpDevice` was inadvertently not added to a session.