Pipenv not activated using "pipenv shell" #10611

Environment data

• VS Code version: 1.43.0
• Extension version (available under the Extensions sidebar): 2020.2.64397
• OS and version: Windows 10
• Python version (& distribution if applicable, e.g. Anaconda): 3.7.6
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): pipenv
• Relevant/affected Python packages and their versions: pipenv 2018.11.26
• Relevant/affected Python-related VS Code extensions and their versions: N/A
• Jedi or Language Server? (i.e. what is "python.jediEnabled" set to; more info How to update the language server to the latest stable version #3977): Jedi
• Value of the python.languageServer setting: Microsoft

Expected behaviour

When opening a terminal in a project with a pipenv environment selected, the environment should be activated using pipenv shell. This seems to be indicated as the expected behavior by the resolution of issue #2855.

Actual behaviour

The pipenv environment is activated using <pipenv dir>/Scripts/activate.ps1. This causes the .env file to not be loaded.

Steps to reproduce:

[NOTE: Self-contained, minimal reproducing code samples are extremely helpful and will expedite addressing your issue]

1. Create a new directory.
2. In a terminal, navigate to the new directory and create a pipenv environment using pipenv shell.
3. Open VS Code on the new directory.
4. Create a new python file in the directory, so the Python extension is loaded.
5. Ensure that the correct pipenv environment is selected.
6. Open a new terminal in VS Code.
7. Observe that the environment is activated using <pipenv dir>/Scripts/activate.ps1 and not pipenv shell.