Python Extension and Python Environment Extension both activate when `python.useEnvironmentsExtension` defaults to false

まだ誰も着手していません。

## Environment data

## Repro Steps

* Install the Python extension
* Install the Python environment extension
* Set the user configuration to:

```json
"workbench.enableExperiments": false,
"python.experiments.enabled": false
```

Reload the window

## Expected behavior

* The Python and Python environment extension agree on which extension is responsible for managing environments

## Actual behavior

* Both extensions activate
* I see two Python selectors
* The `Select Python Environment` selector from the Python Environment extension is missing

## Additional context

The Python Environment Extension uses `inspect` to decide whether `useEnvironmentsExtension` is set to false, but this does not take into account a default value.

The `when` condition of the Command Palette entry uses `when`, which takes default values into account

The Python Extension uses `get`, which takes default values into account

This came up in https://github.com/astral-sh/ty-vscode/issues/551 because it's now unclear which extension ty should consider as being authoritative when it comes to selecting an environment.

まず Python Environment Extension の構成検査とアクティベーションロジックを特定し、次に Python Extension のデフォルトを考慮した get の動作および Command Palette の when condition と比較します。両方の拡張機能をインストールし、実験機能を無効にした状態で再現します。完了の条件は、拡張機能が環境の所有権について一致し、期待されるセレクターだけが表示されることです。

索引モデルが issue の本文から書いたものです。