r/stm_manager: do not warn when some of the stms did not make progress

When a partition is created without the batch cache, the write may not
be immediately visible for the reader. In this case the
`raft::state_machine_manager` identifies it as an issue with the state
machine not being able to make progress. Added a differentiation of the
log level based on the cache configuration of the partition. For the
partitions that uses the cache the `WARN` log level is kept to make it
easy to recognize possibly stuck state machines.

Signed-off-by: Michał Maślanka <michal@redpanda.com>
(cherry picked from commit 53e9fb4)

src/v/raft/state_machine_manager.cc

@@ -371,8 +371,10 @@ ss::future<> state_machine_manager::try_apply_in_foreground() {
           model::no_timeout);
 
         if (max_last_applied == model::offset{}) {
-            vlog(
-              _log.warn,
+            vlogl(
+              _log,
+              _raft->log_config().cache_enabled() ? ss::log_level::warn
+                                                  : ss::log_level::debug,
               "no progress has been made during state machine apply. Current "
               "next offset: {}",
               _next);