filter: Fix sorted_term_types sorting of streams:public.

We had the wrong term type key in the sorting declaration, resulting
in this operator being always sorted last.

frontend_tests/node_tests/filter.js

@@ -1233,6 +1233,11 @@ run_test('term_type', () => {
         ['stream', 'stream', 'topic']
     );
 
+    assert_term_sort(
+        ['search', 'streams-public'],
+        ['streams-public', 'search']
+    );
+
     const terms = [
         {operator: 'topic', operand: 'lunch'},
         {operator: 'sender', operand: 'steve@foo.com'},

static/js/filter.js

@@ -623,7 +623,7 @@ Filter.term_type = function (term) {
 Filter.sorted_term_types = function (term_types) {
     const levels = [
         'in',
-        'streams',
+        'streams-public',
         'stream', 'topic',
         'pm-with', 'group-pm-with', 'sender',
         'near', 'id',