ci: gate golden-comparison codecov upload on has_golden condition

When golden test data is absent, the test step is skipped, leaving no
coverage.xml or golden-results.xml. The codecov upload steps now use
the same `steps.check_golden.outputs.has_golden == 'true'` guard as the
test step so they are skipped rather than failing or uploading nothing.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Signed-off-by: Justin Chu <justinchuby@users.noreply.github.com>

Author: justinchuby

.github/workflows/main.yml

@@ -233,13 +233,13 @@ jobs:
             --junitxml golden-results.xml
         timeout-minutes: 30
       - name: Upload coverage to Codecov
-        if: always()
+        if: steps.check_golden.outputs.has_golden == 'true'
         uses: codecov/codecov-action@v6
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           flags: golden
       - name: Upload test results to Codecov
-        if: ${{ !cancelled() }}
+        if: steps.check_golden.outputs.has_golden == 'true' && !cancelled()
         uses: codecov/codecov-action@v6
         with:
           token: ${{ secrets.CODECOV_TOKEN }}