fix: Fix provider string for AzureTokenProvider #3407

Job	Run time
lint	50s
mypy (./packages/autogen-core)	2m 7s
mypy (./packages/autogen-magentic-one)	1m 5s
mypy (./packages/agbench)	53s
mypy (./packages/autogen-ext)	1m 56s
codecov (./packages/autogen-core)	1m 1s
mypy (./packages/autogen-agentchat)	1m 31s
codecov (./packages/autogen-magentic-one)	1m 47s
docs (./packages/autogen-core)	1m 40s
mypy (./packages/magentic-one-cli)	1m 21s
codecov (./packages/autogen-ext)	3m 11s
docs-example-check (./packages/autogen-core)	2m 33s
codecov (./packages/autogen-agentchat)	1m 8s
format	59s
pyright (./packages/autogen-core)	55s
samples-code-check	58s
test (./packages/autogen-core)	1m 9s
pyright (./packages/autogen-magentic-one)	1m 13s
test (./packages/autogen-magentic-one)	1m 29s
pyright (./packages/agbench)	50s
test (./packages/autogen-ext)	3m 0s
pyright (./packages/autogen-ext)	1m 18s
test (./packages/autogen-agentchat)	1m 9s
pyright (./packages/autogen-agentchat)	53s
pyright (./packages/magentic-one-cli)	1m 0s
check-proto-changes-python	1m 4s
markdown-code-lint	2m 10s
	39m 10s

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