[Lens] Allow refreshing Lens component

[flash1293]

With the current API it's not possible to refresh a Lens component. There should be a way to cause the embeddable to re-render. The easiest way is probably passing in an observable as a prop which, on emitting, triggers a refresh.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[stratoula]

@ThomThomson I think with your work on embeddables redesign this will be possible as they are more react-ish right?

[ThomThomson]

Yes, each react embeddable will return an imperative API, and that API could have a refresh function on it, or even an Observable like @flash1293 originally suggested.

I can work on an example that shows how manual refreshing would work.

[stratoula]

@ThomThomson yes this is what I mean. This will be possible with the new service, correct?

[ThomThomson]

Oh! I misread your initial comment. Now I've edited mine for clarity. Yes, this will be possible.