Backfill product_categories in event/metric definitions for group:pipeline_execution

What does this MR do and why?

Last year, product_category was removed from event/metric definitions because it wasn't being used by the Data team. However, it's become clear that Product still needs this mapping, and that metrics & events should be able to belong to multiple product categories if needed.

This MR reintroduces the values for product_category from ~1 year ago under the product_categories field for grouppipeline execution.

Some of the categories from a year ago either no longer exist today or have been renamed/combined. In these cases, I took a best guess at what the new category is. Please double check that the added product_categories are the correct ones for each metric/event.

This MR includes these feature categories: review_apps, code_quality, code_testing, continuous_integration

References

• Re-fill `product_categories` for metrics with e... (#473401 - closed)

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