Python: pseudo-stream copilot invoke_stream

[moonbox3]

Motivation and Context

The current copilot studio client doesn't support streaming invocation. The underlying orchestration patterns rely on agents to have an invoke_stream. Since it doesn't exist in the copilot agent, that agent type cannot be used. This PR implements a pseudo-invoke_stream so that the agent can be used with patterns - although it doesn't stream the response back in chunks, it unblocks the use if one desired to use our new orchestration patterns.

Description

• Closes Python: Bug: CopilotStudioAgent in Orchestration gets stuck, always timeout #12449

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
agents/copilot_studio
copilot_studio_agent.py	246	246	0%	3–8, 10, 15–16, 20, 25, 27–30, 34–37, 42–47, 52, 60, 66–70, 73–74, 77, 88–94, 96–97, 99, 103–105, 109–112, 114, 116, 118, 120–121, 125–129, 131–132, 139–141, 145–147, 149–150, 153, 158, 161, 163, 166–167, 172–173, 178, 180–185, 187–190, 192–194, 203–204, 207, 218–220, 222–223, 225–226, 228, 230–231, 233, 235–237, 239, 241–242, 244–246, 248–255, 257–258, 265–266, 269–270, 272, 297–298, 300, 305–312, 314–315, 320–321, 325–326, 328, 330, 332–334, 336–337, 374–375, 377–378, 393–394, 396–398, 400, 404, 415, 419–421, 442, 448–449, 451, 453–454, 462, 464, 466–468, 491, 497–498, 500, 502, 510, 512–513, 544, 550–551, 553, 555–556, 564, 566–568, 574, 583–584, 586, 588–589, 591, 593–595, 597–598, 600, 602, 604–606, 611–613, 616, 618, 620–621, 623–627, 630, 632–633, 635–636, 638–639, 641–644, 646–647, 653, 661–662, 667
TOTAL	26431	4518	82%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3638	22 💤	0 ❌	0 🔥	1m 55s ⏱️