Move ClusterApplierService assertion after logging exception (#132446)

#120087 moved the assertion to the beginning of the catch block, before the warning log message.
To ease future development, this PR moves the assertion back, so the warning will be available in the logs if a dev unexpectedly runs into this assertion.

Author: JeremyDahlgren

server/src/main/java/org/elasticsearch/cluster/service/ClusterApplierService.java

@@ -469,9 +469,6 @@ private void runTask(String source, Function<ClusterState, ClusterState> updateF
                 );
                 warnAboutSlowTaskIfNeeded(executionTime, source, stopWatch);
             } catch (Exception e) {
-                // failing to apply a cluster state with an exception indicates a bug in validation or in one of the appliers; if we
-                // continue we will retry with the same cluster state but that might not help.
-                assert applicationMayFail();
                 timedListener.onFailure(e);
                 TimeValue executionTime = getTimeSince(startTimeMillis);
                 if (logger.isTraceEnabled()) {
@@ -492,6 +489,9 @@ private void runTask(String source, Function<ClusterState, ClusterState> updateF
                         e
                     );
                 }
+                // failing to apply a cluster state with an exception indicates a bug in validation or in one of the appliers; if we
+                // continue we will retry with the same cluster state but that might not help.
+                assert applicationMayFail();
             } finally {
                 clearIsApplyingClusterState();
             }