Add update tests for pullAll

[vic-tsang]

This PR contains:

• update tests for pullAll
• test_array_cross_operator.py - cross-operator interactions between array update operators

Ref:

• Issue Add compatibility test for $pullAll #385

[documentdb-triage-tool]

🤖 Auto-triaged by documentdb-triage-tool.

Applied: compatibility test, enhancement
Project fields suggested: Component test-coverage · Priority P2 · Effort L · Status Needs Review
Confidence: 0.85 (mixed)

Reasoning

component from path globs (test-coverage); effort from diff stats (846+0 LOC, 9 files); LLM: Adds new test coverage for the pullAll update operator and cross-operator array interactions, expanding the compatibility test suite.

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