feat(controller): clusterconfig-schema-split task 3 — fix test fixtures for shrunk cluster_config_t

Drops the two cfg.port = ...; struct-literal assignments in
test_commit_barrier_rollout.c and test_config_repl.c (removed field, task
1.2). Repo-wide sweep found no other genuine cluster_config_t literal
referencing a removed field.

Full clean build now succeeds (153/153 targets) and controller_unit_test
passes 976/976 with zero new failures.

src/controller/testsuite/test_config_repl.c

@@ -980,7 +980,6 @@ static uint8_t *t43_make_config_blob(size_t *len_out)
 
     memset(&cfg, 0, sizeof(cfg));
     cfg.clustername       = (char *)"t43-upgrade";
-    cfg.port              = 9991;
     cfg.config_generation = 1;
 
     capn_init_malloc(&cap);