adds integration test for the InMemoryRuntime (#4659) #2338

Job	Run time
format	57s
lint	46s
check-proto-changes-python	1m 2s
docs-example-check (./packages/autogen-core)	2m 15s
docs (./packages/autogen-core)	1m 59s
mypy (./packages/autogen-core)	1m 57s
pyright (./packages/autogen-core)	59s
mypy (./packages/autogen-magentic-one)	1m 15s
pyright (./packages/autogen-magentic-one)	56s
test (./packages/autogen-core)	50s
mypy (./packages/agbench)	57s
pyright (./packages/agbench)	1m 2s
test (./packages/autogen-magentic-one)	1m 27s
pyright (./packages/autogen-ext)	57s
mypy (./packages/autogen-ext)	1m 45s
test (./packages/autogen-ext)	2m 11s
pyright (./packages/autogen-agentchat)	1m 4s
test (./packages/autogen-agentchat)	1m 5s
mypy (./packages/autogen-agentchat)	1m 3s
	24m 27s

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