onnxruntime

ce6aaeec - Skip file path validation in CreateEpContextModel when the output is not a file (#28431)

Skip file path validation in CreateEpContextModel when the output is not a file (#28431) ### Description A file output path is needed when: - Writing the output model to a file (not to a buffer or write function) - Writing initializers to an external file (needs the model path to compute the external file location) otherwise the file output path validation can be skipped. ### Motivation and Context <!-- - Why is this change required? What problem does it solve? - If it fixes an open issue, please link to the issue here. --> When compiling a model via the Compile API in a sandboxed environment, CreateEpContextModel() would attempt to validate/generate a file output path, even when the user explicitly set the output to a buffer via SetOutputModelBuffer(). This caused std::filesystem::exists() to throw an "Access is denied" exception on the dummy model path _MODEL_EDITOR_API_MODEL_, because the sandbox restricts filesystem access.