Fix Iceberg min/max pruning lost under object_storage_cluster

Under `object_storage_cluster` (distributed object-storage reads), the WHERE
predicate did not reach `ReadFromCluster`, so Iceberg min/max file pruning was
silently skipped (`IcebergMinMaxIndexPrunedFiles=0`) and selective queries
scanned the whole table. Measured on IcebergBench q16: 3.16B vs 78.7M rows,
~7.0s vs ~0.8s (~60x read amplification).

The prune-only `ObjectFilterStep` that carries the predicate to the cluster
task iterator (`getTaskIteratorExtension`) was gated on `use_hive_partitioning`,
so a non-hive Iceberg cluster read got a null filter. Add `ObjectFilterStep`
for any `ReadFromCluster` with a WHERE, not just hive-partitioned tables.
`ObjectFilterStep::updatePipeline` is a no-op, so it never filters rows on the
initiator -- required at `WithMergeableState`, where the filter columns may be
absent from the blocks returned by cluster replicas.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: UnamedRus

src/Planner/Planner.cpp

@@ -170,7 +170,6 @@ namespace Setting
     extern const SettingsBool serialize_string_in_memory_with_zero_byte;
     extern const SettingsString temporary_files_codec;
     extern const SettingsNonZeroUInt64 temporary_files_buffer_size;
-    extern const SettingsBool use_hive_partitioning;
 }
 
 namespace ServerSetting
@@ -2460,8 +2459,15 @@ void Planner::buildPlanForQueryNode()
 
     if (query_processing_info.isSecondStage() || query_processing_info.isFromAggregationState())
     {
-        if (settings[Setting::use_hive_partitioning]
-            && !query_processing_info.isFirstStage()
+        /// Deliver the WHERE predicate to distributed object-storage reads (ReadFromCluster) for
+        /// object/file pruning: Iceberg min/max & partition pruning, Hive partition pruning, etc.
+        /// ObjectFilterStep is prune-only (its updatePipeline is a no-op), so it never filters rows
+        /// on the initiator -- required here because at WithMergeableState the filter columns may not
+        /// exist in the blocks returned by cluster replicas. This must NOT be gated on
+        /// use_hive_partitioning: otherwise a non-hive Iceberg cluster read gets a null filter and
+        /// min/max pruning is silently skipped (IcebergMinMaxIndexPrunedFiles=0 -> full-table
+        /// over-read on selective queries).
+        if (!query_processing_info.isFirstStage()
             && expression_analysis_result.hasWhere())
         {
             if (typeid_cast<ReadFromCluster *>(query_plan.getRootNode()->step.get()))