Revert "add warump script for az cli (actions#10126)"

This reverts commit fcf7cd1.

images/ubuntu/scripts/build/install-azure-cli.sh

@@ -12,11 +12,4 @@ echo "azure-cli https://docs.microsoft.com/en-us/cli/azure/install-azure-cli-lin
 rm -f /etc/apt/sources.list.d/azure-cli.list
 rm -f /etc/apt/sources.list.d/azure-cli.list.save
 
-echo "Warmup 'az'"
-az --help > /dev/null
-if [ $? -ne 0 ]; then
-    echo "Command 'az --help' failed"
-    exit 1
-fi
-
 invoke_tests "CLI.Tools" "Azure CLI"