fix: revert redis-primary-cpu back to 95
What
Revert !5136 (merged) and set the SLO back to 95.
Why
The EOC got paged on this SLO violation because CPU reached 80%. Looking back 1 week we reach the 80% threshold fairly often. At the moment we can't scale this fleet horizontally as pointed out in !5136 (merged) so the EOC can't do anything.
Reference: gitlab-com/gl-infra/production#8064 (closed)
Edited by Steve Xuereb