legends are not wrapped correctly

When there are multiple legends, lets-plot have hard time to fit them into to canvas. I have an example below to demonstrate the problem. This one is with gggrid but I happened to encounter the problem with single plots when there are multiple legends, I can provide examples if needed.

Here is the multi-legend overflow example. There should be 7 legends shown, but only 3 (2 of them partially) appear. I am aware that this is an extreme case, but this can happen with even two legends.

> Note that: I highlighted the plot borders (red), legend borders (blue) and grid border gray!

I believe legends should wrap automatically (may be in a grid format) and/or the canvas should grow to fit all the legends.

No source files or tests are named. Start by reproducing the attached gggrid multi-legend overflow example and trace the legend layout path for multiple legends in both grid and single-plot cases. Done means all legends are visible, wrapped or accommodated by a larger canvas, including cases with only two legends.

Written by the indexing model from the issue text.