Support Spring 6.1.x ThreadPoolTaskScheduler lifecycle changes/late-shutdown

See [Support spring 6.1.x lifecycle changes/late-shutdown for pubsub publisher scheduler](https://github.com/GoogleCloudPlatform/spring-cloud-gcp/pull/2738)

1. Determine if these updates (or similar) should be applied to:
* Pubsub scheduler configuration
* Other modules in Spring Cloud GCP that use the ThreadPoolTaskScheduler

2. Update configuration setting docs for updates made by the above step

Start by reviewing the linked pull request 2738 and locating the Pub/Sub scheduler configuration plus other ThreadPoolTaskScheduler uses across the repository. Check the related configuration setting documentation. Done means determining which modules need equivalent Spring 6.1.x lifecycle updates and documenting all configuration changes.

Written by the indexing model from the issue text.