Python: Docs: Add Microsoft Agent Framework successor callout to READMEs #29252

Job	Run time
paths-filter	9s
Python Pre-Merge Integration Tests - Memory (incl samples using those)	0s
Python Pre-Merge Integration Tests - Multi-Modality	0s
python-integration-tests-check	3s
Python Integration Tests - Scheduled run	0s
Python Pre-Merge Integration Tests - Agents	0s
Python Pre-Merge Integration Tests - AI Services (incl samples using those)	0s
Python Pre-Merge Integration Tests - Ollama	0s
	12s

Provide feedback