Python: AgentExecutor keeps service_session_id when replaying full conversation

[moonbox3]

Description

AgentExecutor keeps session.service_session_id when a downstream executor is invoked with a replayed full conversation (including prior function-call/tool-result items).

This can cause provider calls to include both:

• a server-side continuation pointer (previous_response_id via service_session_id), and
• the same historical items explicitly in input.

Expected behavior: when full conversation is explicitly replayed to an agent executor, service_session_id should be cleared/reset before agent.run(...).

Steps To Reproduce

1. Run:

   pytest packages/core/tests/workflow/test_full_conversation.py::test_run_request_with_full_history_clears_service_session_id --runxfail -q

2. Observe assertion failure that the downstream spy agent still sees resp_PREVIOUS_RUN.

Code Sample

# Existing repro in repo:
# packages/core/tests/workflow/test_full_conversation.py
# test_run_request_with_full_history_clears_service_session_id

Error Messages / Stack Traces

E       AssertionError: assert 'resp_PREVIOUS_RUN' is None
E        +  where 'resp_PREVIOUS_RUN' = <...>._captured_service_session_id

Package Versions

• agent-framework-core: 1.0.0rc2
• agent-framework-orchestrations: 1.0.0b260225
• Source commit tested: 02ba27493 (main)

Python Version

Python 3.13.5

Additional Context

Likely area:

• packages/core/agent_framework/_workflows/_agent_executor.py (from_response, _run_agent*)

Related xfail note in test references issue #4047.