Add session_duration to access policies & orgs

[GreenStage]

Description

Pending documentation update
Adds session_duration to access policies & organizations.
The API already supports these, but they are undocumented

Has your change been tested?

Unit tests

Screenshots (if appropriate):

Types of changes

What sort of change does your code introduce/modify?

• Bug fix (non-breaking change which fixes an issue)
• [X ] New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [X ] My code follows the code style of this project.
• [ X] My change requires a change to the documentation.
• [ X] I have updated the documentation accordingly.
• [X ] I have added tests to cover my changes.
• [X ] All new and existing tests passed.
• [X ] This change is using publicly documented in cloudflare/api-schemas
  and relies on stable APIs.

[github-actions]

changelog detected ✅

[jacobbednarz]

lgtm once the API schemas are updated 🏆

[github-actions]

This functionality has been released in v0.79.0.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!