Add missing glm::vec3 color member to HPPVertex struct

[SRSaunders]

Description

Add missing glm::vec3 color member to HPPVertex struct.

Tested on macOS Ventura.

Fixes #1161

General Checklist:

Please ensure the following points are checked:

• [x] My code follows the coding style
• [x] I have reviewed file licenses
• [x] I have commented any added functions (in line with Doxygen)
• [x] I have commented any code that could be hard to understand
• [x] My changes do not add any new compiler warnings
• [x] My changes do not add any new validation layer errors or warnings
• [x] I have used existing framework/helper functions where possible
• [x] My changes do not add any regressions
• [x] I have tested every sample to ensure everything runs correctly

• [x] This PR describes the scope and expected impact of the changes I am making

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  • [x] I did a full batch run using the batch command line argument to make sure all samples still work properly

Sample Checklist

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[SaschaWillems]

Merging this, as it's urgent.

Again thank you very much for spotting this and providing a PR. Very much appreciated 👍🏻

[SRSaunders]

Happy to help out where I can. Thx.