Added projection test cases for $slice

[vic-tsang]

This PR contains:

• projection test cases for $slice
• introduced skip_rejection_types for BSON comparison test cases as the engine converted some of the projection slice into valid expression slice which didn't result in error (the skipped test cases are tested outside the framework from line 189 in test_slice_projection_behavior.py)
• renamed error code EXPRESSION_SLICE_NOT_ARRAY_ERROR to SLICE_INVALID_ARGUMENT_ERROR

Ref:

• Issue Add compatibility test for projection operators (3 total) #29

[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, test-framework); effort from diff stats (1167+1 LOC, 11 files); LLM: Adds new projection test cases for the $slice operator under the compatibility tests path, expanding test coverage for an existing feature.

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