fix: selected is nil if its number is padded

Author: Bekaboo

lua/fzf-lua/providers/ui_select.lua

@@ -48,7 +48,7 @@ end
 
 M.accept_item = function(selected, o)
   if #selected == 0 then return end
-  local idx = selected and tonumber(selected[1]:match("^(%d+)%.")) or nil
+  local idx = selected and tonumber(selected[1]:match("^%s*(%d+)%.")) or nil
   o._on_choice(idx and o._items[idx] or nil, idx)
   o._on_choice_called = true
 end