Update the VM image used for the PowerShell 7 worker in Functions V3 for integration tests

[Francisco-Gamino]

2016 VMs are no longer supported in Azure Dev Ops. We should update the pipeline to use MMS2019TLS for Windows builds. For more info, please see: https://github.com/Azure/azure-functions-powershell-worker/blob/dev/azure-pipelines-e2e-integration-tests.yml#L9-L19

File to be updated: https://github.com/Azure/azure-functions-powershell-worker/blob/v3.x/ps7/azure-pipelines-e2e-integration-tests.yml#L9-L17

[Francisco-Gamino]

This issue has been fixed. For more info, please see #843.