chore(flags): add more metrics for new flags service

[dmarticus]

Flags service is almost ready to hit with real traffic but I want to see how the metrics are looking, so I'm adding in some metrics around common access paths, including:

• pulling the team information from redis
• pulling flags information from redis
• pulling cohort information from application-persisted in-memory cache vs postgres
• pulling property information request-persisted in-memory cache vs postgres
• failures to update redis
• failures to evaluate flags

[havenbarnes]

this seems to have some same diffs as #26444? Mostly focused on the metrics you added, they look great!

[dmarticus]

this seems to have some same diffs as #26444? Mostly focused on the metrics you added, they look great!

yeah my b, forgot to change the branch origination. Just updated.