We've observed errors during shutdown like the following:
```
ERROR 2023-12-26 17:36:17,413 [shard 0:main] raft - [088f01a3-a18b-4821-b027-9f49e55c1926] applier fiber stopped because of the error: std::_Nested_exception<raft::state_machine_error> (State machine error at raft/server.cc:1230): std::runtime_error (forward_service is shutting down)
INFO 2023-12-26 17:36:17,413 [shard 0:strm] storage_service - raft_state_monitor_fiber aborted with raft::stopped_error (Raft instance is stopped)
ERROR 2023-12-26 17:36:17,413 [shard 0:strm] storage_service - raft topology: failed to fence previous coordinator raft::stopped_error (Raft instance is stopped, reason: "background error, std::_Nested_exception<raft::state_machine_error> (State machine error at raft/server.cc:1230): std::runtime_error (forward_service is shutting down)")
```
some CQL statement execution was trying to use `forward_service` during
shutdown.
It turns out that the statement is in
`system_keyspace::load_topology_state`:
```
auto gen_rows = co_await execute_cql(
format("SELECT count(range_end) as cnt FROM {}.{} WHERE key = '{}' AND id = ?",
NAME, CDC_GENERATIONS_V3, cdc::CDC_GENERATIONS_V3_KEY),
gen_uuid);
```
It's querying a table in the `system` keyspace.
Pushing local table queries through `forward_service` doesn't make sense
as the data is not distributed. Excluding local tables from this logic
also fixes the shutdown error.
Fixesscylladb/scylladb#16570Closesscylladb/scylladb#16662
d93074e87e