ci: enable tracking of policy enforcement latency in scale test

[marseel]

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Fixes: #issue-number

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[marseel]

hmm, seems like I might be missing some other config. Some of the queries are not giving any results:

2024-05-14T11:45:05.5266079Z W0514 11:45:05.525624    7212 generic_query_measurement.go:169] query returned no samples for Network Policy Enforcement Latency: PolicyCreation - TargetCount
2024-05-14T11:45:05.5267897Z I0514 11:45:05.525729    7212 generic_query_measurement.go:208] bounded query: histogram_quantile(0.5, sum(policy_enforcement_latency_policy_creation_seconds_bucket)