fix(tree): prevent node expansion when double-clicking checkbox

[YueCHEN195]

What it does

Currently, in the TreeWidget, rapid consecutive clicks (a double-click) on a node's checkbox will bubble up to the tree node row. Because the checkbox only stops the propagation of onClick but not onDoubleClick, the handleDblClickEvent of the tree row is triggered. This results in the unintended behavior where double-clicking a checkbox causes the tree node to expand or collapse.

This PR fixes the issue by adding an onDoubleClick event handler to the checkbox <input> element in renderCheckbox and calling e.stopPropagation(). This ensures that double-click events on the checkbox are consumed by the checkbox itself and do not trigger the tree node's default expansion/collapse behavior.

How to test

1. Open or implement any view in Theia that utilizes a TreeWidget with checkboxes enabled (i.e., nodes returning valid checkboxInfo).
2. Rapidly double-click on the checkbox of a collapsible node (a directory/folder node).
3. Before this PR: The checkbox state toggles, but the tree node also expands/collapses unexpectedly.
4. After this PR: The checkbox state toggles rapidly, and the tree node remains in its current expansion state without expanding or collapsing.

Breaking changes

• This PR introduces breaking changes and requires careful review. If yes, the breaking changes section in the changelog has been updated.

Attribution

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