ci: Merge CI and Loadtest workflows

The reason why those workflows were split in the first place was just to obtain loadtest
results quicker, because the in the separated workflow, only the single loadtest job
needs to finish before the artifacts can be downloaded.

However, the disadvantage of this approach was, that the results were not as easily
accessible as they could be in a single workflow. Additionally, it's possible to depend
on the "prepopulate nix" job for efficiency if the loadtest runs in the main workflow.

.github/workflows/report.yaml

@@ -2,7 +2,7 @@ name: Upload Reports
 
 on:
   workflow_run:
-    workflows: ["Loadtest"]
+    workflows: ["CI"]
     types:
       - completed
 
@@ -12,7 +12,6 @@ jobs:
     permissions:
       checks: write
     runs-on: ubuntu-latest
-    if: ${{ github.event.workflow_run.conclusion == 'success' }}
     steps:
       - name: Download from Artifacts
         uses: dawidd6/action-download-artifact@v3