Update integration metrics to reflect product category ownership

Follow-up from !223012 (merged): Add product category - import vol. 1

Context:

config/metrics/**/*.yml define internal metrics with associated product group and feature category. Many of the integration metrics are assigned to groupimport, but more correctly belong to other groups.

The related MR spawned this discussion around whether to re-assign the product group.

https://handbook.gitlab.com/handbook/product/cross-stage-features/

Objective:

Ensure all integration metrics are correctly attributed to the groups that now own them following the product category reorganization.

Related:

• !223012 (merged) Add product category - import vol. 1