FIX: Handle uncaught exception (#11263)

After the search term is parsed for advanced search filters, the term may
become empty. Later, the same term will be passed to Discourse.route_for
which will raise an ArgumentError.

> URI(nil)
ArgumentError: bad argument (expected URI object or URI string)

lib/discourse.rb

@@ -412,7 +412,7 @@ module Discourse
     unless uri.is_a?(URI)
       uri = begin
         URI(uri)
-      rescue URI::Error
+      rescue ArgumentError, URI::Error
       end
     end