onnxruntime

445dcff7 - Add ORT_UNIT_TEST_MAIN_DYNAMIC_PLUGIN_EP_CONFIG_JSON_FILE env var (#27945)

Add ORT_UNIT_TEST_MAIN_DYNAMIC_PLUGIN_EP_CONFIG_JSON_FILE env var (#27945) ### Description <!-- Describe your changes. --> Add support for specifying dynamic plugin EP configuration via a JSON file path in the ORT_UNIT_TEST_MAIN_DYNAMIC_PLUGIN_EP_CONFIG_JSON_FILE environment variable. This is mutually exclusive with the specifying inline JSON using the existing ORT_UNIT_TEST_MAIN_DYNAMIC_PLUGIN_EP_CONFIG_JSON environment variable. ### 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. --> Allow more flexibility in specifying configuration. It may be impractical to put everything in an environment variable.