According to my experience, deploy function by clicking the button in VS code sometimes may occur unexpected error message. You can deploy your function by using command func azure functionapp publish <functionAppName> --build remote instead.
Before run the command in your VS code, you need to create a function app first on azure portal. Please choose python 3.7 like below screenshot show when you create the function app on portal(to avoid version issue) because it seems your local python function is 3.7. Then run the command in "Terminal" window of your VS code to deploy the code from local to azure. I usually use this deployment method and always works fine.

func azure functionapp publish <functionAppName> --build remotein VS code to deploy your function from local to azure. - Hury Shen