rich media: add try/rescue to ensure we catch parsing and fetching failures

lib/pleroma/web/rich_media/parser.ex

@@ -21,9 +21,14 @@ def parse(url) do
   end
 
   defp parse_url(url) do
+    try do
       {:ok, %Tesla.Env{body: html}} = Pleroma.HTTP.get(url)
 
       html |> maybe_parse() |> get_parsed_data()
+    rescue
+      _e ->
+        {:error, "Parsing error"}
+    end
   end
 
   defp maybe_parse(html) do