explicitly depend on typing_extensions

[zjma]

What is the change being pushed?

explicitly install typing_extensions in task python script.

Why are you pushing this change?

CI is broken by this.

How is this implemented?

n/a

Type of change

Devtool.

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I identified and added all keyless stakeholders and component owners affected by this change as reviewers
• I tested both happy and unhappy path of the functionality
• I have made corresponding changes to the documentation