fix: Firefox + Linux custom shader issue with glsl compiler attribute optimization

[eonarheim]

===:clipboard: PR Checklist :clipboard:===

• 📌 issue exists in github for these changes
• 🔬 existing tests still pass
• 🙈 code conforms to the style guide
• 📐 new tests written and passing / old tests updated with new scenario(s)
• 📄 changelog entry added (or not needed)

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This PR fixes an issue where Firefox on Linux would throw an error when using custom Materials due to unused attributes caused by glsl compiler optimization.

Before it would throw and crash excalibur

Now after, it will log a warning because this is potentially a bug, or at minimum something you should look at