Fixed Matrix Multiplication Shaders

[GGajanan1]

Description

Fixed Matrix Multiplication in shaders
fixes #4250

Issue number and link

Testing plan

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• I have submitted a Contributor License Agreement
• I have added my name to CONTRIBUTORS.md
• I have updated CHANGES.md with a short summary of my change
• I have added or updated unit tests to ensure consistent code coverage
• I have updated the inline documentation, and included code examples where relevant
• I have performed a self-review of my code

[github-actions]

Thank you for the pull request, @GGajanan1! Welcome to the Cesium community!

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[GGajanan1]

Thank you for the pull request, @GGajanan1! Welcome to the Cesium community!

In order for us to review your PR, please complete the following steps:

• Send in a Contributor License Agreement (CLA)
• Add yourself to the contributors file

Review Pull Request Guidelines to make sure your PR gets accepted quickly.