Improve migrating old editorAssociations setting format

[sandy081]

This PR fixes #125970

• Perform migration only from active window
• Respect old format while reading the setting value

[alexdima]

👍 Nice!

[bpasero]

Minor nit: if the this.hostService.hadLastFocus() would move into convertOldAssociationFormat, we could also protect from the following case:

• user has 10 windows opened
• user manually changes settings in a way that we start the migration
• all 10 windows start to migrate the setting at the same time

[lramos15]

I'm not sure what the difference between last focus and focus is. Here is what I thought the change would look like.

		if (this.hostService.hasFocus) {
			this.convertOldAssociationFormat();
		}
		this.hostService.onDidChangeFocus((e) => {
			if (this.hostService.hasFocus) {
				this.convertOldAssociationFormat();
			}
		});

That way once any window gets focused we would convert the format. I would argue that since we convert so aggressively we should either call convertOldAssociationFormat() in the read if we somehow still read an old setting. We are duplicating the logic over into the read to be the same as update but if we always update on focus then it should never be the old setting.

[bpasero]

We simply mimic what other code was already doing, like release notes that wants to open them only in the active window but not all windows, so we have a bit of confidence that that works:

vscode/src/vs/workbench/contrib/update/browser/update.ts

Line 161 in dc4b317

hostService.hadLastFocus().then(async hadLastFocus => {

[sandy081]

if the this.hostService.hadLastFocus() would move into convertOldAssociationFormat,

@bpasero Good point. Done 👍

@lramos15 Let me know if the changes are good. I will push then and we can trigger the builds.