refactor(saturation): update gitaly active node ratio to 0.25
What
Update the ratio to be 0.25 instead of 0.20
Why
Part of the multi-project migration
we are going to combine the marquee
shard
in the default
shard. We'll do this at the end of the migraton, after
we've moved the default
shard. To make sure that the marquee shards
get distributed evenly we will change the cut off to be at 75% so when
we are done we'll increase it back to 80% and distribute the marquee
shard evenly to the existing Gitaly storage.
Reference: https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/24553