feat(rule_engine): also bump `unknown` counter for unrecoverable action errors

Fixes https://emqx.atlassian.net/browse/EMQX-11494

apps/emqx_bridge/test/emqx_bridge_v2_SUITE.erl

@@ -968,7 +968,8 @@ t_rule_pointing_to_non_operational_channel(_Config) ->
                         counters :=
                             #{
                                 matched := 1,
-                                'actions.failed' := 1
+                                'actions.failed' := 1,
+                                'actions.failed.unknown' := 1
                             }
                     },
                     emqx_metrics_worker:get_metrics(rule_metrics, RuleId)

apps/emqx_rule_engine/src/emqx_rule_runtime.erl

@@ -580,7 +580,8 @@ inc_action_metrics(RuleId, Result) ->
 do_inc_action_metrics(RuleId, {error, {recoverable_error, _}}) ->
     emqx_metrics_worker:inc(rule_metrics, RuleId, 'actions.failed.out_of_service');
 do_inc_action_metrics(RuleId, {error, {unrecoverable_error, _}}) ->
-    emqx_metrics_worker:inc(rule_metrics, RuleId, 'actions.failed');
+    emqx_metrics_worker:inc(rule_metrics, RuleId, 'actions.failed'),
+    emqx_metrics_worker:inc(rule_metrics, RuleId, 'actions.failed.unknown');
 do_inc_action_metrics(RuleId, R) ->
     case is_ok_result(R) of
         false ->