Fix promote-images-prod after splitting it out (#10292)

## Problem
`promote-images` was split into `promote-images-dev` and
`promote-images-prod` in
https://github.com/neondatabase/neon/pull/10267.

`dev` credentials were loaded in `promote-images-dev` and `prod`
credentials were loaded in `promote-images-prod`, but
`promote-images-prod` needs `dev` credentials as well to access the
`dev` images to replicate them from `dev` to `prod`.

## Summary of changes
Load `dev` credentials in `promote-images-prod` as well.

.github/workflows/build_and_test.yml

@@ -979,6 +979,16 @@ jobs:
       VERSIONS: v14 v15 v16 v17
 
     steps:
+      - name: Configure AWS credentials
+        uses: aws-actions/configure-aws-credentials@v4
+        with:
+          aws-region: eu-central-1
+          role-to-assume: ${{ vars.DEV_AWS_OIDC_ROLE_ARN }}
+          role-duration-seconds: 3600
+
+      - name: Login to Amazon Dev ECR
+        uses: aws-actions/amazon-ecr-login@v2
+
       - uses: docker/login-action@v3
         with:
           username: ${{ secrets.NEON_DOCKERHUB_USERNAME }}