Return `connected` pill to evaluate activity refactor

We need to bring back the `connected` pill on the workspace page to evaluate the consistency of activity reporting.


Previously, it always showed `connected` as opening a workspace in the dashboard was recorded as user activity. When returned, it should only report user activity as outlined in the [internal RFC](https://www.notion.so/coderhq/Definitions-of-Workspace-Usage-Autostop-Dormancy-e7fa8ff782a948c19bbe4ef8315c26cb):

Actions qualifying as usage:
- Starting, stopping, or restarting a workspace,
- Accessing a `coder_app` running inside a workspace through the Web UI (e.g. `code-server` or Web Terminal),
- Connecting to a workspace via `coder ssh`
- Connecting to an application inside the workspace via `coder port-forward`, or via shared port.

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We will associate the pill with the workspace activity refactor experiment (currently enables the feature, should revert the feature before 2.15 release).

workspace ページと既存のアクティビティリファクタリング実験から始め、続いて対象となる利用アクションについて、リンクされている内部 RFC を読んでください。以前の `connected` pill の実装を見つけ、一覧にある workspace アクションと接続アクションだけがアクティビティを報告する状態で、pill が戻ることを確認してください。

索引モデルが issue の本文から書いたものです。