RDoc-3792 AI connection strings: Enable prompt caching

[Danielle9897]

Issue link

https://issues.hibernatingrhinos.com/issue/RDoc-3792/AI-connection-strings-Enable-prompt-caching

Additional description

Updated articles:

• OpenAI connection string article - Add the new field
• Azure OpenAI connection string article - Add the new field
• Google AI connection string article:
  • Add missing section - "Configuring a chat model"
  • Add the new field

Note:
The PR includes the new property in the Client API section only for the C# client.
The Node.js and Python clients do not support this property yet.
The Studio image was updated for ALL clients.

Type of change

• Content - docs
• Content - cloud
• Content - guides
• Content - start pages/other
• New docs feature (consider updating /templates or readme)
• Bug fix
• Optimization
• Other

Changes in docs URLs

• No changes in docs URLs
• Articles are restructured, URLs will change, mapping is required (update /scripts/redirects.json file, set Documents Moved PR label)

Changes in UX/UI

• No changes in UX/UI
• Changes in UX/UI (include screenshots and description)