Embeddings for all issues for Duo Customers

Description

In #456918 (closed) we are adding issue embeddings for a subset of the gitlab groups' issues only: public and recently updated.

We want to figure out how this can be released to all issues (and decide if that's the end goal or not). This includes getting consent/opt-in from customers (data being sent to a 3rd party) and dealing with cases where some issues have embeddings and some don't.

If we're still ultimately just sending the embeddings to Vertex and nowhere else (aside from GitLab) I don't see any reason we'd be doing anything problematic, assuming it's a Duo customer and they've already agreed to sending their data to Vertex.