Fix manifest download workflow selection

[0xRobin]

CUR2-1437
Changes dbt CI/deploy manifest downloads to look at the latest completed dbt_deploy run, not only the latest successful one. This lets failed deploys that still upload a current manifest advance state for later PR/deploy runs.

[cursor]

PR Summary

Low Risk
Workflow-only change to artifact selection; no dbt models or credentials logic touched.

Overview
Updates dbt CI and dbt deploy so dawidd6/action-download-artifact pulls prod-manifest-latest from the most recent completed dbt_deploy run on main, not only the latest successful one.

Both workflows now set workflow_conclusion: completed, with comments noting that failed deploys can still upload a current manifest (deploy already uploads with if: always()). That keeps PR state comparison and deploy’s own state:modified logic aligned with the newest compiled manifest even when a deploy job fails after compile/upload.

^{Reviewed by Cursor Bugbot for commit 7fdcee5. Configure here.}