chore(spanner): skip running tests for archived samples (#17059)

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Fixes #<issue_number_goes_here> 🦕

Author: sakthivelmanii

packages/google-cloud-spanner/samples/pytest.ini

@@ -0,0 +1,2 @@
+[pytest]
+norecursedirs = .* build dist *.egg venv virtualenv node_modules archived