As you have obviously discovered, the search terms are now encrypted in the URL referrer string, so that option no longer exists. The only workaround I have found it to use your Search term reports to gradually add each search term that triggers your ads as an exact match and phrase match keywords, which you can extract from the URL.
While it is far from perfect, it does allow you to capture the correct data for ~95% of your conversions, or more, depending on how long you have been working on it. This is something you ought to be doing anyway. I was already adding all known search terms to ad campaigns anyway, so it wasn’t any extra effort for me.