Python: DevUI: support having both an agent and a workflow with the same in discovery

[ReubenBond]

Motivation and Context

Currently, if we have both an agent and a workflow with the same id, the backend does not know which one the frontend is interested in when it requests entity info, so it must choose arbitrarily.

This PR adds an optional 'type' parameter which lets the backend distinguish.

This enables representing a workflow as both an agent (using .AsAIAgent()) and as a workflow, with both views on the entity being visible in DevUI.

This PR removes the 'hack' we had in place to prevent the devui from crashing:

if (agent.GetType().Name == "WorkflowHostAgent")
{
    // HACK: ignore WorkflowHostAgent instances as they are just wrappers around workflows,
    // and workflows are handled below.
    continue;
}

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
TOTAL	13066	1922	85%

report-only-changed-files is enabled. No files were changed during this commit :)

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
1745	107 💤	0 ❌	0 🔥	35.064s ⏱️

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[thangchung]

Currently, I have got the same issue described in this PR

I used: Microsoft.Agents.AI.DevUI 1.0.0-preview.251110.1

[jeffhandley]

Code review looks good. I'll fire off some end-to-end tests, but don't block on that.