The button that can quickly start LiveShare is missing.

[linette-zyy]

Describe the bug

Steps to Reproduce

1. Create a new Python application
2. Check this interface

Expected behavior
There should be a button in the upper right corner that can quickly launch LiveShare。

Additional context and screenshots
The button that can quickly start LiveShare is missing.

I can only open liveshare from File-> Start Live Share Session

[StellaHuang95]

This is an upstream issue not a PTVS one: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2444326