test: do not rely on replication in more read cases

Some read cases were missing in #404 test stabilization commit. This
patch updates missing read cases.

1. https://github.com/tarantool/crud/actions/runs/7322196516/job/19943422319

Follows #404

test/integration/ddl_sharding_info_reload_test.lua

@@ -662,7 +662,8 @@ pgroup_key_change.test_pairs = function(g)
         pairs_eval,
         {
             'customers',
-            {{'==', 'id', 1}, {'==', 'name', 'Emma'}, {'==', 'age', 22}}
+            {{'==', 'id', 1}, {'==', 'name', 'Emma'}, {'==', 'age', 22}},
+            {mode = 'write'},
         })
 
     -- Assert operation bucket_id is computed based on updated ddl info.
@@ -671,6 +672,7 @@ pgroup_key_change.test_pairs = function(g)
         {
             'customers',
             {{'==', 'id', 1}, {'==', 'name', 'Emma'}, {'==', 'age', 22}},
+            {mode = 'write'},
         })
     t.assert_equals(err, nil)
     t.assert_equals(obj, {test_customers_age_tuple})