c/backend: wait for leader to be elected before finishing abort cancel

When forcibly aborting reconfiguration we should wait for the new leader
to be elected in the configuration that the partition was forced to.
This way we can be certain that the new configuration will finally be
replicated to the majority of nodes even tough the leader may not
exists at the time when configuration is replicated.

Fixes: redpanda-data#9243

Signed-off-by: Michal Maslanka <michal@redpanda.com>
(cherry picked from commit 3948312)

src/v/cluster/controller_backend.cc

@@ -959,7 +959,10 @@ controller_backend::process_partition_reconfiguration(
              * configuration so old replicas are not longer needed.
              */
             if (can_finish_update(
-                  type, target_assignment.replicas, previous_replicas)) {
+                  partition->get_leader_id(),
+                  type,
+                  target_assignment.replicas,
+                  previous_replicas)) {
                 co_return co_await dispatch_update_finished(
                   std::move(ntp), target_assignment);
             }
@@ -1009,12 +1012,14 @@ controller_backend::process_partition_reconfiguration(
 }
 
 bool controller_backend::can_finish_update(
+  std::optional<model::node_id> current_leader,
   topic_table_delta::op_type update_type,
   const std::vector<model::broker_shard>& current_replicas,
   const std::vector<model::broker_shard>& previous_replicas) {
     // force abort update may be finished by any node
     if (update_type == topic_table_delta::op_type::force_abort_update) {
-        return true;
+        return current_leader == _self;
+        ;
     }
     // update may be finished by a node that was added to replica set
     if (!has_local_replicas(_self, previous_replicas)) {

src/v/cluster/controller_backend.h

@@ -340,6 +340,7 @@ class controller_backend
       model::ntp, ss::shard_id, partition_assignment);
 
     bool can_finish_update(
+      std::optional<model::node_id>,
       topic_table_delta::op_type,
       const std::vector<model::broker_shard>&,
       const std::vector<model::broker_shard>&);