Prometheus `meilisearch_nb_tasks` seems to report nothing

[gmourier]

Mentioned by @gabrieltz here

"I upgraded to version 1.3.0 yesterday and used some of the new metrics, however i noticed that the metric meilisearch_nb_tasks{instance="XXXXXX:7700", job="meilisearch", kind="statuses", value="processing"} is zero all the time, even while importing a few million documents in over 700 batches. The /tasks endpoint values were correct though"

[irevoire]

I was able to reproduce it; it’s effectively a bug

[curquiza]

Will be fixed in v1.3.1 and release this week or next week

[curquiza]

Fixed by #3976