`Plotly.restyle` and (`Plotly.update`) throws error if trace indice is invalid or out of bound

[antoinerg]

restyle (and update) should not throw an error if you give invalid trace indices, it should just toss them (this behavior was requested by @alexcjohnson)!

Here's a codepen reproducing the issue: https://codepen.io/anon/pen/RexqKO