Python: .Net: Magentic orchestration to return the last agent message when limits reached

[TaoChenOSU]

Motivation and Context

Related to #12687
Related to #12656

Currently, the Magentic orchestration returns a static message if the max reset limit or the max invocation limit is reached.

Description

Return the last agent response if either of the limit is reached.

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 😄

[crickman]

Might be an opportunity to validate this update in StandardMagenticManagerTests (unit-test)

[moonbox3]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
agents/orchestration
magentic.py	294	56	80%	122–124, 256, 379, 447, 450, 457, 461, 463, 521–522, 524–525, 531, 533–534, 538, 566, 570, 580–582, 585, 590–595, 617, 629–630, 632, 637, 641–642, 644, 646–647, 652, 662–663, 666, 670–671, 677–678, 680, 708, 710, 719–723
TOTAL	26693	4596	82%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3659	22 💤	0 ❌	0 🔥	1m 56s ⏱️