[Engineering System] Build Pipeline (#5796)
[Engineering System] Build Pipeline (#5796)

- Added environment variables into the DevOps pipeline configuration for
    Event Hubs live test needs.  The associated changes to the pipeline variable
    definitions, and linkage to variable groups has already been performed.
markcowl/azure-sdk-for-net,ayeletshpigelman/azure-sdk-for-net,hyonholee/azure-sdk-for-net,AsrOneSdk/azure-sdk-for-net,brjohnstmsft/azure-sdk-for-net,yugangw-msft/azure-sdk-for-net,ayeletshpigelman/azure-sdk-for-net,yugangw-msft/azure-sdk-for-net,AsrOneSdk/azure-sdk-for-net,brjohnstmsft/azure-sdk-for-net,hyonholee/azure-sdk-for-net,jackmagic313/azure-sdk-for-net,stankovski/azure-sdk-for-net,hyonholee/azure-sdk-for-net,brjohnstmsft/azure-sdk-for-net,AsrOneSdk/azure-sdk-for-net,jackmagic313/azure-sdk-for-net,ayeletshpigelman/azure-sdk-for-net,AsrOneSdk/azure-sdk-for-net,hyonholee/azure-sdk-for-net,brjohnstmsft/azure-sdk-for-net,jackmagic313/azure-sdk-for-net,brjohnstmsft/azure-sdk-for-net,stankovski/azure-sdk-for-net,jackmagic313/azure-sdk-for-net,ayeletshpigelman/azure-sdk-for-net,hyonholee/azure-sdk-for-net,jackmagic313/azure-sdk-for-net,yugangw-msft/azure-sdk-for-net