Investigate if both integration propagation services can use upsert_all

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This issue came from this discussion !142261 (comment 1747944245).

There are two services involved in propagating integration settings from instance -> group -> project levels.

(after !142261 (merged) merges at time of writing this is correct):

• Integrations::Propagation::BulkCreate
• Integrations::Propagation::BulkUpdate

The two services uses different methods of inserting data. This issue is to investigate whether we can refactor these classes to both use upsert_all.