Add testtools to test-requirements.txt to fix testscenarios import failure

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Co-authored-by: rzhao271 <7199958+rzhao271@users.noreply.github.com>

Author: Copilot

build/test-requirements.txt

@@ -14,6 +14,7 @@ uvicorn
 django
 testresources
 testscenarios
+testtools
 
 # Integrated TensorBoard tests
 tensorboard