Bug: legend overlaps chart when names are very long

[arikfr]

Here's an example:
https://redash-preview.netlify.app/queries/373/source#647

You can see how it looks like when the names aren't long:
https://redash-preview.netlify.app/queries/373/source#648

Possible solutions:

1. Can we put a maximum size on the legend and cut the names past this value?
2. Can we detect this and switch to legend below chart as we do when the space given to the chart is too small?

Also, somewhat related: how hard will it be to expose the control over the legend position (left/bottom) to the user?

Screenshots

Bad

Good

[susodapop]

I added screenshots for quick reference.

Is this related to #3879 and #3975?