Improve agent authentication OBO flow docs with code samples

[pavinduLakshan]

Document issue type

Type/Bug (Report inaccuracies, outdated information, or missing details in the existing content)

Description

Improve this section by adding practical code samples such as curl requests for the authorize call with all required parameters, so users can easily copy, customize, and quickly try out the flow.

https://is.docs.wso2.com/en/next/guides/agentic-ai/ai-agents/agent-authentication/#ai-agent-acting-on-behalf-of-a-user

Version

latest

[wso2-engineering-bot]

@wso2-engineering-bot create a PR for this issue following repo conventions

[wso2-engineering-bot]

✅ Documentation fix has been created automatically

A pull request has been created in the docs-is repository to address this issue:
🔗 PR Link: wso2/docs-is#6095

What was added:

• Comprehensive curl code samples for the AI agent acting on-behalf-of-user flow
• Step-by-step implementation guide with all required parameters
• Actor token acquisition example
• Authorization request with requested_actor parameter
• Token exchange with delegated access token
• Resource access examples

Versions updated: next, 7.2.0 (via shared include file)

The PR includes practical, copy-paste-ready curl examples that users can easily customize and try out, as requested in this issue.