db: view_update_builder: build_some: maybe yield between updates

`update.move_to` freezes the mutation

Signed-off-by: Benny Halevy <bhalevy@scylladb.com>

db/view/view.cc

@@ -929,6 +929,7 @@ future<utils::chunked_vector<frozen_mutation_and_schema>> view_update_builder::b
     utils::chunked_vector<frozen_mutation_and_schema> mutations;
     for (auto& update : _view_updates) {
         update.move_to(mutations);
+        co_await coroutine::maybe_yield();
     }
     co_return mutations;
 }