feat: add a ClientContext field to Spanner requests (#32336)

feat: add Secure Parameters to the ClientContext

PiperOrigin-RevId: 853323071

Source-Link: googleapis/googleapis@211d22f

Source-Link: googleapis/googleapis-gen@bf515c7
Copy-Tag: eyJwIjoiZ29vZ2xlLWNsb3VkLXNwYW5uZXItdjEvLk93bEJvdC55YW1sIiwiaCI6ImJmNTE1Yzc2MWFiYjg3NWQzMjVjNWQyNDM0NDRhYjA4YmUwYWVjZDUifQ==

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: gcf-owl-bot[bot]