General code health improvement for release

[LTPhantom]

Description

General code health improvement for release

Issues Resolved

• https://github.com/googleads/googleads-mobile-flutter/issues/1036

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]). This will ensure a smooth and quick review process. Updating the pubspec.yaml and changelogs is not required.

• [x] I read the Contributor Guide and followed the process outlined there for submitting PRs.
• [x] My PR includes unit or integration tests for all changed/updated/fixed behaviors (See Contributor Guide).
• [x] All existing and new tests are passing.
• [x] I updated/added relevant documentation (doc comments with ///).
• [x] The analyzer (flutter analyze) does not report any problems on my PR.
• [x] I read and followed the Flutter Style Guide.
• [x] I signed the CLA.
• [x] I am willing to follow-up on review comments in a timely manner.

Breaking Change

Does your PR require plugin users to manually update their apps to accommodate your change?

• [ ] Yes, this is a breaking change (please indicate a breaking change in CHANGELOG.md and increment major revision).
• [x] No, this is not a breaking change.

[malandr2]

Can we resolve https://github.com/googleads/googleads-mobile-flutter/issues/1036 in this PR if possible? Related to code health 🙂

[LTPhantom]

Can we resolve #1036 in this PR if possible? Related to code health 🙂

Sure, I can verify if the changes already do.

[LTPhantom]

Can we resolve #1036 in this PR if possible? Related to code health 🙂

This resolves it now. Added to the PR description