fix: Group handle_info clauses together in LeaderElection

Fixes compilation warning by moving the catch-all handle_info/2 clause
to be immediately after the specific handle_info/2 clauses.

In Elixir, all function clauses with the same name and arity must be
grouped together for pattern matching to work correctly.

This resolves the 'mix compile --warnings-as-errors' failure.

lib/aprsme/cluster/leader_election.ex

@@ -108,6 +108,12 @@ defmodule Aprsme.Cluster.LeaderElection do
     {:noreply, state}
   end
 
+  @impl true
+  def handle_info(msg, state) do
+    Logger.debug("LeaderElection received unexpected message: #{inspect(msg)}")
+    {:noreply, state}
+  end
+
   @impl true
   def handle_call(:is_leader?, _from, state) do
     {:reply, state.is_leader, state}
@@ -118,12 +124,6 @@ defmodule Aprsme.Cluster.LeaderElection do
     {:reply, state.leader_node, state}
   end
 
-  @impl true
-  def handle_info(msg, state) do
-    Logger.debug("LeaderElection received unexpected message: #{inspect(msg)}")
-    {:noreply, state}
-  end
-
   @impl true
   def terminate(reason, state) do
     if state.is_leader do