fix: Better addon downloads (#15173)

Get addon downloads to work without making 2 extra api requests but still verifying checksum.
~Needs https://github.com/cloudquery/cloud/pull/660 to be solved/merged first (internal issue)~

Also updates plugin-pb-go to verify the plugin downloads from the hub ([PR](https://github.com/cloudquery/plugin-pb-go/pull/158))

~We might keep this out and use the AddonWithTeam endpoint which is going to be implemented in the backend soon.~