test: improve waiting on panel suggestion

Author: AntoineGS

tests/child_helper.lua

@@ -135,7 +135,7 @@ function M.new_child_neovim(test_name)
     child.lua([[
       local function suggestion_is_visible()
         lines = vim.api.nvim_buf_get_lines(2, 4, 5, false)
-        return lines[1] and lines[1] ~= "" 
+        return lines[1] and (lines[1] = "789" or lines[1] = "789\r")
       end
 
       vim.wait(5000, function()