fix index error

Author: willmcgugan

src/textual/widgets/_option_list.py

@@ -853,7 +853,10 @@ def render_line(self, y: int) -> Strip:
             style = self.get_visual_style("option-list--option")
 
         strips = self._get_option_render(option, style)
-        strip = strips[line_offset]
+        try:
+            strip = strips[line_offset]
+        except IndexError:
+            return Strip.blank(self.scrollable_content_region.width)
         return strip
 
     def validate_highlighted(self, highlighted: int | None) -> int | None: