CI: Wrap all `if:` conditions in `${{ }}`

CI: Wrap all `if:` conditions in `${{ }}`

While `if:` also works with a bare condition, it is a best practice to always
wrap "dynamic placeholders" in `${{ }}`.

See: https://github.blog/changelog/2026-01-29-github-actions-smarter-editing-clearer-debugging-and-a-new-case-function/#better-if-condition-handling