poetry: poetry.exe breaks after self upgrade on Windows

• I am on the latest Poetry version (sort of).
• I have searched the issues of this repo and believe that this is not a duplicate.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• Windows 10:
• 1.1.13 upgraded to 1.12.0b1:

Issue

When upgrading poetry using poetry self update --preview, poetry is no longer operable.

Log from a fresh poetry 1.1.13 install:

> (Invoke-WebRequest -Uri https://install.python-poetry.org -UseBasicParsing).Content | python - --uninstall
Poetry is not currently installed.
> poetry
Fatal error in launcher: Unable to create process using '"...\AppData\Roaming\pypoetry\venv\Scripts\python.ex
> (Invoke-WebRequest -Uri https://install.python-poetry.org -UseBasicParsing).Content | python -
Retrieving Poetry metadata

# Welcome to Poetry!

This will download and install the latest version of Poetry,
a dependency and package manager for Python.

It will add the `poetry` command to Poetry's bin directory, located at:

...\AppData\Roaming\Python\Scripts

You can uninstall at any time by executing this script with the --uninstall option,
and these changes will be reverted.

Installing Poetry (1.1.13)
Installing Poetry (1.1.13): Creating environment
Installing Poetry (1.1.13): Installing Poetry
Installing Poetry (1.1.13): Creating script
Installing Poetry (1.1.13): Done

Poetry (1.1.13) is installed now. Great!


`poetry --version`

> poetry --version
Poetry version 1.1.13
> poetry self --help
USAGE
      poetry self
  or: poetry self update [--preview] [<version>]

COMMANDS
  update
    Updates Poetry to the latest version.

    <version>            The version to update to.
    --preview            Install prereleases.

GLOBAL OPTIONS
  -h (--help)            Display this help message
  -q (--quiet)           Do not output any message
  -v (--verbose)         Increase the verbosity of messages: "-v" for normal output, "-vv" for more verbose output and
                         "-vvv" for debug
  -V (--version)         Display this application version
  -n (--no-interaction)  Do not ask any interactive question

> poetry self update --preview
Updating Poetry to 1.2.0b1
Updating dependencies                                                                                                   
Resolving dependencies...
Package operations: 1 install, 3 updates, 0 removals

  - Updating cleo (0.8.1 -> 1.0.0a4)                                                                                      
  - Installing entrypoints (0.3)                                                                                          
  - Updating poetry-core (1.0.8 -> 1.1.0a7)                                                                               
  - Updating poetry (1.1.13 -> 1.2.0b1)                                                                                 
Updating the poetry script

Poetry (1.2.0b1) is installed now. Great!
> poetry --version
Traceback (most recent call last):
  File "...\AppData\Local\Programs\Python\Python310\lib\runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "...\AppData\Local\Programs\Python\Python310\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "...\AppData\Roaming\Python\Scripts\poetry.exe\__main__.py", line 4, in <module>
ImportError: cannot import name 'main' from 'poetry.console' (...\AppData\Roaming\pypoetry\venv\lib\site-packages\poetry\console\__init__.py)
> (Invoke-WebRequest -Uri https://install.python-poetry.org -UseBasicParsing).Content | python - --uninstall
Removing Poetry (1.1.13)

I needed to update to 1.2.0b1 due to the bug where I could not install CUDA versions of TorchVision and PyTorch together, but this unfortunately seems to have completely bricked my poetry install, requiring a manual deletion of remaining files.

A fully fresh install with (Invoke-WebRequest -Uri https://install.python-poetry.org -UseBasicParsing).Content | python - --version 1.2.0b1 does seem to work, however.

> (Invoke-WebRequest -Uri https://install.python-poetry.org -UseBasicParsing).Content | python - --version 1.2.0b1
Retrieving Poetry metadata

# Welcome to Poetry!

This will download and install the latest version of Poetry,
a dependency and package manager for Python.

It will add the `poetry` command to Poetry's bin directory, located at:

...\AppData\Roaming\Python\Scripts

You can uninstall at any time by executing this script with the --uninstall option,
and these changes will be reverted.

Installing Poetry (1.2.0b1)
Installing Poetry (1.2.0b1): Creating environment
Installing Poetry (1.2.0b1): Installing Poetry
Installing Poetry (1.2.0b1): Creating script
Installing Poetry (1.2.0b1): Done

Poetry (1.2.0b1) is installed now. Great!

You can test that everything is set up by executing:

`poetry --version`

> poetry --version
Poetry (version 1.2.0b1)