Don't return khepri status when khperi_db is disabled

When khepri_db feature flag is disabled, Khepri servers
are running but are not clustered. In this case `rabbit_khepri:status/0`
shows that all nodes are leaders, which is confusing and scary
(even though actually harmless). Instead, we now just print that mnesia
is in use.

(cherry picked from commit b48d4bf)

Author: mkuratczyk

deps/rabbitmq_cli/lib/rabbitmq/cli/diagnostics/commands/metadata_store_status_command.ex

@@ -14,7 +14,12 @@ defmodule RabbitMQ.CLI.Diagnostics.Commands.MetadataStoreStatusCommand do
   use RabbitMQ.CLI.Core.RequiresRabbitAppRunning
 
   def run([] = _args, %{node: node_name}) do
-    :rabbit_misc.rpc_call(node_name, :rabbit_khepri, :status, [])
+    case :rabbit_misc.rpc_call(node_name, :rabbit_feature_flags, :is_enabled, [:khepri_db]) do
+      true ->
+        :rabbit_misc.rpc_call(node_name, :rabbit_khepri, :status, [])
+      false ->
+         [[{<<"Metadata Store">>, "mnesia"}]]
+    end
   end
 
   use RabbitMQ.CLI.DefaultOutput