[BUG] Iceberg identity partition fallback tests failing after GPU support implementation

[pxLi]

Describe the bug
Build: rapids_it-iceberg-dev/15

7 test cases failed during Iceberg integration tests. All failures occurred in tests that check for GPU fallback behavior with identity partition transforms. The tests expected operations (ReplaceDataExec, WriteDeltaExec, OverwriteByExpressionExec) to fall back to CPU, but the GPU implementation successfully executed these operations instead. This indicates the GPU now supports identity partitioning, but the fallback tests were not updated accordingly.

Error logs:

[gw3] FAILED test_iceberg_delete_fallback_unsupported_partition_transform[identity-cow]
assertion failed: Could not find ReplaceDataExec in the GPU plans:
GpuReplaceData GpuIcebergWrite(table=spark_catalog.default.tmp_table_gw3_758013579_0_gpu, format=PARQUET)

[gw3] FAILED test_iceberg_delete_fallback_unsupported_partition_transform[identity-mor]
assertion failed: Could not find WriteDeltaExec in the GPU plans:
GpuWriteDelta GpuSparkPositionDeltaWrite(table=spark_catalog.default.tmp_table_gw3_146793816_0_gpu)

[gw0] FAILED test_iceberg_merge_fallback_unsupported_partition_transform[identity-cow]
[gw0] FAILED test_iceberg_merge_fallback_unsupported_partition_transform[identity-mor]
[gw4] FAILED test_insert_overwrite_specific_partition_identity_fallback
[gw4] FAILED test_iceberg_update_fallback_unsupported_partition_transform[identity-cow]
[gw0] FAILED test_iceberg_update_fallback_unsupported_partition_transform[identity-mor]

7 failed, 809 passed, 12 skipped, 5 xpassed

Environment details
Spark 3.5.6, Scala 2.13, CUDA 12, Iceberg 1.9.2
Commit: 7fefd7d

[pxLi]

related to #14183

cc @mythrocks @liurenjie1024 to help check, thanks

[liurenjie1024]

Seems we forgot to remove some fallback tests, let me fire a pr to fix it today.

[mythrocks]

I thought I'd gotten the fallback tests. It looks like @liurenjie1024 has addressed this in #14204. Thank you, @liurenjie1024.