Update Cloud Workstations resources in the beta provider.

[modular-magician]

This change adds support for timeout-related fields to the Cloud Workstations config resource, and also updates several others so they can be updated via PATCH to avoid re-creating the underlying resource.

This provides fixes for the following issues:

• Add idle_timeout and running_timeout to google_workstations_workstation_config resource terraform-provider-google#14179
• Support updating google_workstations_workstation_config, rather than delete/recreate terraform-provider-google#14072
• Add auto_sleep to google_workstations_workstation_config terraform-provider-google#13980

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This PR is for Terraform. I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Generated Terraform providers, and ran make test and make lint in the generated providers to ensure it passes unit and linter tests.
• Ran relevant acceptance tests using my own Google Cloud project and credentials (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Release Note Template for Downstream PRs (will be copied)

workstations: supported in-place update for `host` and `container` in `google_workstations_workstation_config` (beta)

workstations: fixed an issue where unsetting the container working directory in `google_workstations_workstations_config` was not propagated to the underlying resource (beta)

workstations: fixed an issue where modifying `persistent_directories` and `encryption_key` would fail with API errors; now updating them will recreate the resource (beta)

Derived from GoogleCloudPlatform/magic-modules#7629