Improve behaviour when passing in multiple KPIs

[Bergam0t]

At the moment, if you pass in multiple KPIs there is a good chance the visual will fail to work. However, this then also prevents you from selecting the summary table or summary matrix.

Easiest workaround is to temporarily filter to a single KPI, then switch to the desired visual and then remove the filter.

Improve this behaviour as it's currently not ideal.