Sync eng/common directory with azure-sdk-tools for PR 4480 (#26992)
Sync eng/common directory with azure-sdk-tools for PR 4480 (#26992)

* Add extra parameters for .net readme path

* Use another way for default value

* Remove custom source

Co-authored-by: sima-zhu <5fef37f6cbdb6842d05e30aec045f2f609cf3db2@microsoft.com>
Azure/azure-sdk-for-python,Azure/azure-sdk-for-python,Azure/azure-sdk-for-python,Azure/azure-sdk-for-python