nova-next: Deploy noVNC from source instead of packages
nova-next: Deploy noVNC from source instead of packages

To help improve early detection of issues with newer noVNC releases the
nova-next job now deploys directly from source.

Depends-On: https://review.opendev.org/c/openstack/devstack/+/816736

Change-Id: Ic14d2b13cbf0369fc752d457d73d65488e6df3f9

mahak/nova,mahak/nova,mahak/nova,openstack/nova,openstack/nova,openstack/nova