Keep attribution in demo

[frodrigo]

Remove the attribution is a bad practice. Avoid to do this in a demo. https://www.openstreetmap.org/copyright

https://github.com/razorness/vue-maplibre-gl/blob/1b0284b1e37ec95102bb22e97414395664d33c06/src/App.vue#L9

[razorness]

You are right. That was just left over from a test if this prop gets applied.