MLE-29267: Fix bad use of null-like value and insufficient logging

[vshaniga]

These changes have already been validated on the develop branch in the PR: #601

Tests

• Ran unit tests → All passed
• Ran 06mlcp test suite → No regression failures were found

[Copilot]

Pull request overview

Fixes several null-handling edge cases and improves diagnostic logging in mlcp/mapreduce code paths, aligning with the validated changes from PR #601 to prevent avoidable NPEs and make failures easier to diagnose.

Changes:

• Prevent NPEs by adding explicit null guards in document reading, split parsing, and archive writing paths.
• Ensure OutputArchive always initializes a zip output stream before writing entries.
• Add error-level logging for security option construction failures before rethrowing configuration exceptions.

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
src/main/java/com/marklogic/mapreduce/utilities/InternalUtilities.java	Adds error logging when SecurityOptions construction fails.
src/main/java/com/marklogic/mapreduce/MarkLogicInputFormat.java	Avoids NPE when ruleUris is absent by guarding add().
src/main/java/com/marklogic/mapreduce/DatabaseDocument.java	Guards stream-to-byte[] buffering when the stream is null; falls back to empty content.
src/main/java/com/marklogic/contentpump/OutputArchive.java	Ensures newOutputStream() is called whenever outputStream is null before putNextEntry().
src/main/java/com/marklogic/contentpump/DatabaseContentReader.java	Adds null checks for item and result to avoid NPEs during metadata/iteration.

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