fix: add unit tests for dotnet and improve test infrastructure #4055

Job	Run time
format	54s
lint	56s
mypy (./packages/autogen-core)	6m 27s
mypy (./packages/autogen-magentic-one)	1m 34s
mypy (./packages/agbench)	1m 8s
mypy (./packages/autogen-ext)	6m 31s
pyright (./packages/autogen-core)	1m 11s
mypy (./packages/autogen-agentchat)	1m 36s
check-proto-changes-python	1m 14s
pyright (./packages/autogen-magentic-one)	1m 21s
mypy (./packages/magentic-one-cli)	1m 24s
pyright (./packages/agbench)	1m 2s
docs (./packages/autogen-core)	1m 40s
pyright (./packages/autogen-ext)	1m 5s
docs-example-check (./packages/autogen-core)	3m 12s
pyright (./packages/autogen-agentchat)	1m 3s
markdown-code-lint	2m 10s
samples-code-check	59s
pyright (./packages/magentic-one-cli)	1m 1s
test (./packages/autogen-core)	1m 15s
test (./packages/autogen-magentic-one)	1m 50s
test (./packages/autogen-ext)	4m 33s
test (./packages/autogen-agentchat)	1m 9s
codecov (./packages/autogen-core)	7s
codecov (./packages/autogen-magentic-one)	8s
codecov (./packages/autogen-ext)	9s
codecov (./packages/autogen-agentchat)	13s
	45m 52s

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