Add tests for untested parts of sub_entity_literals

[john-h-kastner-aws]

Description of changes

Address one area of low coverage code identified in #1515

Issue #, if available

Checklist for requesting a review

The change in this PR is (choose one, and delete the other options):

• A breaking change requiring a major version bump to cedar-policy (e.g., changes to the signature of an existing API).
• A backwards-compatible change requiring a minor version bump to cedar-policy (e.g., addition of a new API).
• A bug fix or other functionality change requiring a patch to cedar-policy.
• A change "invisible" to users (e.g., documentation, changes to "internal" crates like cedar-policy-core, cedar-validator, etc.)
• A change (breaking or otherwise) that only impacts unreleased or experimental code.

I confirm that this PR (choose one, and delete the other options):

• Updates the "Unreleased" section of the CHANGELOG with a description of my change (required for major/minor version bumps).
• Does not update the CHANGELOG because my change does not significantly impact released code.

I confirm that cedar-spec (choose one, and delete the other options):

• Does not require updates because my change does not impact the Cedar formal model or DRT infrastructure.
• Requires updates, and I have made / will make these updates myself. (Please include in your description a timeline or link to the relevant PR in cedar-spec, and how you have tested that your updates are correct.)
• Requires updates, but I do not plan to make them in the near future. (Make sure that your changes are hidden behind a feature flag to mark them as experimental.)
• I'm not sure how my change impacts cedar-spec. (Post your PR anyways, and we'll discuss in the comments.)

I confirm that docs.cedarpolicy.com (choose one, and delete the other options):

• Does not require updates because my change does not impact the Cedar language specification.
• Requires updates, and I have made / will make these updates myself. (Please include in your description a timeline or link to the relevant PR in cedar-docs. PRs should be targeted at a staging-X.Y branch, not main.)
• I'm not sure how my change impacts the documentation. (Post your PR anyways, and we'll discuss in the comments.)

[github-actions]

Coverage Report

Head Commit: b2124efb2cf0e70914023f74d3bbe39567edaac2

Base Commit: 4177c20278256af6ce36e7d904910f5c339dd8b7

Download the full coverage report.

Coverage of Added or Modified Lines of Rust Code

Required coverage: 80.00%

Actual coverage: 100.00%

Status: PASSED ✅

Details

File	Status	Covered	Coverage	Missed Lines

Coverage of All Lines of Rust Code

Required coverage: 80.00%

Actual coverage: 81.35%

Status: PASSED ✅

Details

Package	Status	Covered	Coverage	Base Coverage
cedar-policy	🔴	3059/4392	69.65%	--
cedar-policy-cli	🔴	538/927	58.04%	--
cedar-policy-core	🟢	11495/13770	83.48%	--
cedar-policy-formatter	🟢	914/1043	87.63%	--
cedar-policy-validator	🟢	8242/9647	85.44%	--
cedar-wasm	🔴	0/29	0.00%	--

[adpaco-aws]

Coverage: 📈