Add usage tracking for Repository commit comments
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### Description
This issue suggests adding usage tracking for the Repository commit comments so that we can get a better idea of how often this feature is used.
### Resources
- [Data For Product Managers](https://about.gitlab.com/handbook/business-technology/data-team/programs/data-for-product-managers/)
- [Product Intelligence Guide](https://about.gitlab.com/handbook/product/product-intelligence-guide/)
- [Metrics Dictionary (for reference)](https://metrics.gitlab.com/snowplow/)
- [Implement Snowplow tracking](https://docs.gitlab.com/ee/development/snowplow/implementation.html)
issue