Focused item in tree is never unfocused

<!-- ⚠️⚠️ Do Not Delete This! bug_report_template ⚠️⚠️ --> <!-- Please read our Rules of Conduct: https://opensource.microsoft.com/codeofconduct/ --> <!-- 🕮 Read our guide about submitting issues: https://github.com/microsoft/vscode/wiki/Submitting-Bugs-and-Suggestions --> <!-- 🔎 Search existing issues to avoid creating duplicates. --> <!-- 🧪 Test using the latest Insiders build to see if your issue has already been fixed: https://code.visualstudio.com/insiders/ --> <!-- 💡 Instead of creating your report here, use 'Report Issue' from the 'Help' menu in VS Code to pre-fill useful information. --> <!-- 🔧 Launch with `code --disable-extensions` to check. --> Does this issue occur when all extensions are disabled?: **No** - issue with trees contributed by any extension <!-- 🪓 If you answered No above, use 'Help: Start Extension Bisect' from Command Palette to try to identify the cause. --> <!-- 📣 Issues caused by an extension need to be reported directly to the extension publisher. The 'Help > Report Issue' dialog can assist with this. --> - VS Code Version: 1.75.0-insider - OS Version: Darwin x64 22.2.0 <details> <summary>VS Code details</summary> Version: 1.75.0-insider Commit: 1379f0375440df946adc62f7afb8375dd45d5adf Date: 2023-01-17T05:21:02.509Z Electron: 19.1.9 Chromium: 102.0.5005.194 Node.js: 16.14.2 V8: 10.2.154.23-electron.0 OS: Darwin x64 22.2.0 Sandboxed: Yes </details> Steps to Reproduce: I edited the tree-view-sample extension to provide a minimal reproducible example https://github.com/alexweininger/vscode-extension-samples/tree/alex/focus-never-unset/tree-view-sample 1. Clone and run the edited tree-view-sample 2. Before selecting or focusing any tree items, click the "Test View: Change Title" button on the view title bar. <img width="572" alt="image" src="https://user-images.githubusercontent.com/12476526/213016670-31b859b7-b69d-406c-b88b-70ee0f8b9c81.png"> Observe that the `focusedNode` and `selectedNode` arguments are both undefined as expected…