[EuiDataGrid] Overflow hidden on cells

[timroes]

Currently the data grid cells don't have an overflow: hidden on it, causing the data grid to potentially look a bit weird if there's e.g. images in the cells:

I wonder if we should by default set overflow: hidden on cells to make it look (imho) better:

But I am not sure if there might be other side-effects why we're considering having overflow visible.

[cee-chen]

Looks like overflow: hidden was added in #5194 🎉