feat(sdk/cli): add extra header for cli (#4400)
feat(sdk/cli): add extra header for cli (#4400)

In some cases, it may need extra header to handle the API calls.
Directly add `header_name` and `header_value` props in
`.config/kfp/context.json` and pass the name/value pair
to APIClient.

Here is one of the use cases:
if the service is protected by istio RBAC and need JWT header
for authentication, you can specify the JWT id-token in
the .config/kfp/context.json with these two new props.
The id-token would be carried in the specified header name.
Then the API call can be properly authentiecated and checked
if the user has the permission to access the service.
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