Update OAI_CONFIG_LIST_sample (#655)

* Update OAI_CONFIG_LIST_sample

replace to api_base from base_url.  api_base is the correct name, otherwise it will error with invalid URL

* put base_url back, add a comment that "api_base" should be used for v0.1.x

* fix typo

* Update OAI_CONFIG_LIST_sample

grammar fix

Co-authored-by: Chi Wang <wang.chi@microsoft.com>

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Co-authored-by: Li Jiang <bnujli@gmail.com>
Co-authored-by: Chi Wang <wang.chi@microsoft.com>