[CQ] AddToAppUtils: fix deprecated API use and unchecked calls

[pq]

Migrate to future-safe modulesAdded API and fix unchecked calls.

(Removing another bit of noise from the run console.)

See: #7718.

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read the Flutter Style Guide recently, and have followed its advice.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

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