Don't paste to active editor when a tab is closed by mouse wheel click

[dsseng]

What it does

Fixes a bug

How to test

Part A (Bug reproduction, on master branch):

1. Open two editor tabs
2. Focus on one tab (cursor should be in editor)
   
   (In my case my cursor is in the Landing.vue editor, I can edit there and I close launch.json)
3. Close the other tab with mouse wheel click
4. See that clipboard content was pasted into active editor
   Part B (Testing the fix):
5. Try to reproduce bug from part A
6. See that the tab just closes

Tested in Firefox 76

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

[paul-marechal]

Tested on Firefox 75, works like a charm!

[akosyakov]

@marechal-p please merge, code wise it does not seem to have big impact