Unjustified RBR API access error ?

Hi,

I noticed something weird with the RBR web-API:

when accessing one sensor metadata from ``/instruments/{sn}/argometadatajson``,
the returned JSON has some url for each parameter pointing toward pre-deployment certificates,
these urls are under the ``predeployment_vendorinfo.certificate`` key.

However, despite using a valid API key, a 401 Unauthorized error is raised when trying to access this certificate url.

On the other hand, a direct request to the ``/instruments/{sn}/certificates`` endpoint,
works like a charm returning a zip file with all PDF of certificates.

This looks like an unjustified access error, since we can get access to the same documents (I guess), using another web-API endpoint.

It would be awesome to fix this inconsistency. Two possibilities I see:
1. (best) fix access rights to allow direct download to one parameter ``predeployment_vendorinfo.certificate`` url using a valid API key
2. modify all parameter ``predeployment_vendorinfo.certificate`` urls to point toward the autorized ``/instruments/{sn}/certificates`` endpoint

all the best

poke @jeanmichelleconte