(see #154465 and #3130)

Verification steps:
Set:

"editor.mouseMiddleClickAction": "ctrlLeftClick",

... check that in the editor whenever you use the middle mouse button to click on text, that behaves as if you used ctrl+left click.

Set:

"editor.mouseMiddleClickAction": "openLink",

... check that when you use the middle mouse button to click on a link, that link opens (otherwise middle mouse click has default behavior, i.e. nothing should happen).