Scope

• Update error returns in mongocrypt_ctx_provide_kms_providers to set the ctx->state to MONGOCRYPT_CTX_ERROR

Background & Motivation
An error in a context function is expected to set the state of the context as MONGOCRYPT_CTX_ERROR. Some drivers require this behavior for correctness. For example, the Node.JS bindings do not always check the return values of some mongocrypt_ctx_* functions, and may rely on the context state to return an error.