Fix interactivity when only 'cartodb_id' is selected

[rubenmoya]

Related to: #2089

Description

This PR changes how we check if a layer is interactive or not.

The problem is that we were checking this.getInteractiveColumnNames().length > 1 because we always add cartodb_id by default, so when adding it manually the check was false.

[jesusbotella]

The change looks good but I'm missing some real world tests.

You are mocking method's response and if you change the method's specification, your test will pass even though it shouldn't.

What about doing something like this:

const layer = new carto.layer.Layer(cartoSource, cartoStyle, {
  featureClickColumns: ['cartodb_id']
});

expect(layer.isInteractive()).toBe(true);

[jesusbotella]

I've tested this PR in local and Builder and seems like it works like a charm.

I've tested that you can edit, select, and the popups are shown successfully. ✨