CI: Push to PyPI directly if pushing to TestPyPI succeeds?

[leofang]

Today, our release workflow requires a manual loop over

• release components
• release versions (for cuda-bindings we release 12.x and 13.x at the same time)
• target indices (TestPyPI/PyPI): https://github.com/NVIDIA/cuda-python/blob/36b8c5fa799ddd9b8c9eb8b4816258485cbeeb7c/.github/workflows/release.yml#L34-L40

However, some might argue that at least the last step could be automated if pushing to TestPyPI works. I like having more human in the loop because it gives us time to click around TestPyPI links and feel comfortable clicking the button one last time for official release, but we haven't had any issues where things work on TestPyPI but not on PyPI, so this automation might be safe enough.