paws-public: increase the timeout for read at the nginx proxy
paws-public: increase the timeout for read at the nginx proxy

In some cases, notebooks can take a fair while for the renderer to
render. As is, the nbserve pod will just timeout and disconnect, causing
a 504.

Deployment of this in the current state will require manually building
the image, since we haven't re-established the deploy hook properly yet.

Bug: T270820

yuvipanda/paws,yuvipanda/paws