Do not return raw operators from narrow.operators().

Even in the case where we are running embedded narrows,
we want narrow.operators() to return new-style operators
that you get with Filter objects, so that callees do
not need to support the legacy tuple format.

(imported from commit a6649881a926a2304e9f7cc8ca53b406e2c8828e)

static/js/narrow.js

@@ -26,7 +26,7 @@ exports.predicate = function () {
 
 exports.operators = function () {
     if (current_filter === undefined) {
-        return page_params.narrow;
+        return new Filter(page_params.narrow).operators();
     }
     return current_filter.operators();
 };