gh-36496: build*.yml: Fix application of CI fixes broken in #36442

    
<!-- ^^^^^
Please provide a concise, informative and self-explanatory title.
Don't put issue numbers in there, do this in the PR body below.
For example, instead of "Fixes #1234" use "Introduce new method to
calculate 1+1"
-->
<!-- Describe your changes here in detail -->

<!-- Why is this change required? What problem does it solve? -->
Fixes the failure as seen e.g. in https://github.com/sagemath/sage/actio
ns/runs/6599334101/job/17928255227?pr=36271#step:7:8
<!-- If this PR resolves an open issue, please link to it here. For
example "Fixes #12345". -->
<!-- If your change requires a documentation PR, please link it
appropriately. -->

### 📝 Checklist

<!-- Put an `x` in all the boxes that apply. -->
<!-- If your change requires a documentation PR, please link it
appropriately -->
<!-- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->
<!-- Feel free to remove irrelevant items. -->

- [x] The title is concise, informative, and self-explanatory.
- [ ] The description explains in detail what this PR is about.
- [ ] I have linked a relevant issue or discussion.
- [ ] I have created tests covering the changes.
- [ ] I have updated the documentation accordingly.

### ⌛ Dependencies

<!-- List all open PRs that this PR logically depends on
- #12345: short description why this is a dependency
- #34567: ...
-->

<!-- If you're unsure about any of these, don't hesitate to ask. We're
here to help! -->
    
URL: #36496
Reported by: Matthias Köppe
Reviewer(s): Kwankyu Lee

.ci/retrofit-worktree.sh

@@ -12,6 +12,10 @@ export GIT_AUTHOR_EMAIL="[email protected]"
 export GIT_COMMITTER_NAME="$GIT_AUTHOR_NAME"
 export GIT_COMMITTER_EMAIL="$GIT_AUTHOR_EMAIL"
 
+# Set globally for other parts of the workflow
+git config --global user.name "$GIT_AUTHOR_NAME"
+git config --global user.email "$GIT_AUTHOR_EMAIL"
+
 set -ex
 
 # If actions/checkout downloaded our source tree using the GitHub REST API