Enable feature flags to resume artifact removal on self-managed

What does this MR do and why?

Enable Feature Flags required to resume artifact removal on self-managed by default:

• ci_detect_wrongly_expired_artifacts
• ci_destroy_all_expired_service

For self-managed users to be able to resume artifact removal, they need both feature flags enabled. However, SaaS cannot have ci_detect_wrongly_expired_artifacts enabled, because we want to remove non-trace artifacts on SaaS as well. The reason for that is detailed in the linked MR comment.

As a result, there are 2 permutations of the feature flags:

Environment	ci_detect_wrongly_expired_artifacts	ci_destroy_all_expired_service	Feature flag source of truth
SaaS	false	true - only after background migration is completed	chatops
Self-managed	true	true	yaml

In order to release this change safely, without inadvertently enabling the flags on SaaS, we need to ensure that the 2 feature flags have been explicitly disabled on production through chatops.

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Related to #353128 (closed) #354955 (closed)