Open plugin editor view on single click

[colin-grant-work]

What it does

This PR changes the event handling in the VSX tree views so that a single click on a tree node opens the editor view (main-panel view) for the plugin, and clicking on interactables within the node does not select the node. These changes bring us a bit closer to VSCode's behavior.

How to test

1. Open the extensions view.
2. Click on a tree node.
3. Observe that the plugin editor view opens.
4. Double click on a tree node.
5. Observe that the plugin editor view opens only once (if it wasn't already open)
6. Click on a button inside a non-selected node (gear, install, uninstall)
7. Observe that the action associated with that button takes place, but the node is not selected.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

Signed-off-by: Colin Grant colin.grant@ericsson.com

[vince-fugnitto]

The changes work well for me 👍

• only a single-click is needed to open an editor
• editors are only opened once, if not already opened
• actions such as install do not require the extension to be active
• using the arrow keys and enter to open editors still works
• no visible regressions