Fix block positions lookups in spatial join

[raunaqmorarka]

Description

Previous code was using underlying value position of one channel on another channel's block.
This can give incorrect results when one of channels uses an RLE or Dictionary block.

Additional context and related issues

Seems to be broken since de3c160

Release notes

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## General
* Fix incorrect results with spatial joins. ({issue}`26021`)

[Copilot]

Pull Request Overview

This PR fixes incorrect block position lookups during spatial joins, addressing potential errors with channels using RLE or Dictionary blocks.

• Update block position lookup in the spatial index supplier to correctly derive the underlying value position.
• Adjust probe partition lookup to use the correct row index.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
core/trino-main/src/main/java/io/trino/operator/PagesSpatialIndexSupplier.java	Corrects block position retrieval logic for geometry channels.
core/trino-main/src/main/java/io/trino/operator/PagesRTreeIndex.java	Uses the proper index for probe partition lookup.

Comments suppressed due to low confidence (2)

core/trino-main/src/main/java/io/trino/operator/PagesSpatialIndexSupplier.java:112

• [nitpick] The variable name 'chennelBlock' appears to be a typo. Consider renaming it to 'channelBlock' for clarity.

            Block chennelBlock = channels.get(geometryChannel).get(blockIndex);

core/trino-main/src/main/java/io/trino/operator/PagesRTreeIndex.java:156

• The change from 'probePosition' to 'position' should be verified to confirm it correctly indexes into the partition data according to the intended row mapping.

        int probePartition = probePartitionChannel.map(channel -> INTEGER.getInt(probe.getBlock(channel), position)).orElse(-1);