🧪🚑 Pass a Codecov config to the action @ GHA (#12508) (#12513)

The #11921 update broke uploading coverage of the `main` branch (or
any in-repo pushes for that matter) to Codecov 4 months ago.
Version 4 requires an upload token to be provided and since there was
no configuration for it, the upload was failing. But the step itself
was showing up as successful due to `fail_ci_if_error: true` being
set. The error is visible in the console output, though.

This patch flips the setting to `fail_ci_if_error: false` and sets the
Codecov upload token in the config in clear text. The non-secret part
allows the PRs uploads to be more stable.

Co-authored-by: Ronny Pfannschmidt <opensource@ronnypfannschmidt.de>
(cherry picked from commit 9947ec3ad1)

Co-authored-by: Sviatoslav Sydorenko (Святослав Сидоренко) <wk@sydorenko.org.ua>

.github/workflows/test.yml

@@ -222,9 +222,8 @@ jobs:
     - name: Upload coverage to Codecov
       if: "matrix.use_coverage"
       uses: codecov/codecov-action@v4
-      continue-on-error: true
       with:
-        fail_ci_if_error: true
+        fail_ci_if_error: false
         files: ./coverage.xml
         verbose: true