[Identity] Suppress stdin for subprocess-based creds

[pvaneck]

In some cases, the underyling executable being called hangs waiting for user input. When calling the executables we can ignore stdin.

Closes: #31493

[azure-sdk]

API change check

API changes are not detected in this pull request.

[xiangyan99]

Do other languages also need this?

[pvaneck]

Do other languages also need this?

I am not certain on the stdin behavior in other languages. but I did bring this up to the group a few weeks back. I know an issue about this was already opened in the Java repo.

I can verify and open issues with other languages if the issue is recreatable.

[christothes]

Do other languages also need this?

I am not certain on the stdin behavior in other languages. but I did bring this up to the group a few weeks back. I know an issue about this was already opened in the Java repo.

I can verify and open issues with other languages if the issue is recreatable.

We already have an issue for this in .NET also Azure/azure-sdk-for-net#32993

[pvaneck]

Checked JS/Go and they don't appear to hang for stdin when auto-upgrade is enabled for az. So I believe each affected language should have issues open regarding this.