[Test] Fix the metadata lease override in DataNode unit tests (#18953)

Use the DataNode check interval instead of the ConfigNode fence threshold so unit tests without ConfigNode heartbeats do not fence shared metadata caches after 20 seconds.

Author: Caideyipi

iotdb-core/datanode/src/test/resources/iotdb-system.properties

@@ -29,7 +29,7 @@ dn_sync_dir=target/sync
 dn_seed_config_node=127.0.0.1:10710
 
 # Unit tests do not receive ConfigNode heartbeats, so disable the background metadata lease check.
-metadata_lease_fence_ms=9223372036854775807
+check_dn_lease_status_interval_ms=9223372036854775807
 
 udf_lib_dir=target/ext/udf
 trigger_lib_dir=target/ext/trigger