conan: [bug] Conan 2.0 fails to find Visual Studio Build Tools using the 'MSBuildToolchain'

Environment details

• Operating System+version: Windows 10
• Compiler+version: msvc 2019 build tools
• Conan version: 2.0.0
• Python version: 3.9

Steps to reproduce

1. Install the msvc 2019 build tools (a.k.a Visual Studio 16)
2. In a recipe, use the generator ‘MSBuildToolchain’
3. and build

It fails finding the Visual Studio 16 Build Tools installation with an error:

ERROR: Error in generator 'MSBuildToolchain': VS non-existing installation: Visual Studio 16

Note: I already tried to manually activate vcvars, but conan still does not find the installation.

Logs

======== Finalizing install (deploy, generators) ========
conanfile.py (qt/5.15.8): Writing generators to C:\src\qt-conan\5.x.x
conanfile.py (qt/5.15.8): Generator 'MSBuildToolchain' calling 'generate()'
conanfile.py (qt/5.15.8): MSBuildToolchain created conantoolchain_release_x64.props
conanfile.py (qt/5.15.8): MSBuildToolchain writing conantoolchain.props
conanfile.py (qt/5.15.8): ERROR: Traceback (most recent call last):
  File "c:\local\miniforge3\lib\site-packages\conans\client\generators\__init__.py", line 70, in write_generators
    generator.generate()
  File "c:\local\miniforge3\lib\site-packages\conan\tools\microsoft\toolchain.py", line 104, in generate
    VCVars(self._conanfile).generate()
  File "c:\local\miniforge3\lib\site-packages\conan\tools\microsoft\visual.py", line 139, in generate
    vcvars = vcvars_command(vs_version, architecture=vcvarsarch, platform_type=None,
  File "c:\local\miniforge3\lib\site-packages\conan\tools\microsoft\visual.py", line 216, in vcvars_command
    cmd.append('call "%s" ' % _vcvars_path(version, vs_install_path))
  File "c:\local\miniforge3\lib\site-packages\conan\tools\microsoft\visual.py", line 232, in _vcvars_path
    raise ConanException("VS non-existing installation: Visual Studio %s" % version)
conans.errors.ConanException: VS non-existing installation: Visual Studio 16

ERROR: Error in generator 'MSBuildToolchain': VS non-existing installation: Visual Studio 16