formatter: use Pleroma.HTML module instead of HtmlSanitizeEx directly

lib/pleroma/formatter.ex

@@ -193,7 +193,7 @@ def get_custom_emoji() do
 
   # TODO: make it use something other than @link_regex
   def html_escape(text, "text/html") do
-    HtmlSanitizeEx.basic_html(text)
+    HTML.filter_tags(text)
   end
 
   def html_escape(text, "text/plain") do