tests: skip topic_delete_unavailable_test in debug mode

To pass reliably, this test requires that object storage
PUTs complete promptly enough to complete within
the 5 second graceful leaderhip transfer window.  Otherwise
orphan objects can be left behind and fail the test's expectation
of a clean delete.

tests/rptest/tests/topic_delete_test.py

@@ -15,6 +15,7 @@
 from ducktape.mark import matrix, parametrize
 from requests.exceptions import HTTPError
 
+from rptest.utils.mode_checks import skip_debug_mode
 from rptest.services.cluster import cluster
 from rptest.clients.types import TopicSpec
 from rptest.clients.offline_log_viewer import OfflineLogViewer
@@ -270,6 +271,7 @@ def topic_delete_installed_snapshots_test(self):
                    timeout_sec=30,
                    backoff_sec=1)
 
+    @skip_debug_mode  # Rely on timely uploads during leader transfers
     @cluster(
         num_nodes=3,
         log_allow_list=[