Do not draw tables that can't be drawn

This is a temporary fix for undrawable tables until we've
implemented a proper strategy. What this does is that it replaces
an undrawable table with an ellipsis (...). This should only
occur in either super big tables or deeply nested tables in a
console with a small buffer width.

src/Spectre.Console/Widgets/Paragraph.cs

@@ -193,6 +193,12 @@ namespace Spectre.Console
 
         private List<SegmentLine> SplitLines(RenderContext context, int maxWidth)
         {
+            if (maxWidth <= 0)
+            {
+                // Nothing fits, so return an empty line.
+                return new List<SegmentLine>();
+            }
+
             if (_lines.Max(x => x.CellWidth(context)) <= maxWidth)
             {
                 return Clone();