MLE-21825 Bumped Spark compile dependency to 3.5.6

[rjrudin]

No description provided.

[Copilot]

Pull Request Overview

This PR updates the project to use Apache Spark 3.5.6 by bumping version references in build configs and docs.

• Bump sparkVersion in gradle.properties and update release notes link
• Update Spark dependency from 3.5.5 to 3.5.6 in example build.gradle files
• Refresh documentation (docs/index.md and CONTRIBUTING.md) to recommend Spark 3.5.6

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
gradle.properties	Updated sparkVersion to 3.5.6 and release notes
examples/java-dependency/build.gradle	Bumped Spark SQL dependency to 3.5.6
examples/entity-aggregation/build.gradle	Bumped Spark SQL dependency to 3.5.6
docs/index.md	Changed recommended Spark version to 3.5.6
CONTRIBUTING.md	Updated sdkman install instructions to 3.5.6

Comments suppressed due to low confidence (2)

gradle.properties:2

• [nitpick] The comment still references Spark 3.5.3. Consider updating or removing outdated context now that we're on 3.5.6, and note any relevant bug fixes in this release.

# the Spark connector plumbing between 3.5.0 and 3.5.3. This also bumps Jackson to 2.15.2.

CONTRIBUTING.md:153

• The numbered list item is split across two lines and the continuation (building against Spark 3.5.6.) is not indented. Merge into a single sentence or indent the second line to preserve markdown list formatting.

1. Use [sdkman to install Spark](https://sdkman.io/sdks#spark). Run `sdk install spark 3.5.6` since we are currently

[sonarqube-progress-marklogic]

Quality Gate passed

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