Remove `absoluteServerTimes` switch

[ioannakok]

They were introduced as an experiment to improve caching:

• Absolute dates & times on server #10154

A the moment the switch is off and will not be enabled in the near future as this would require design and product input. This ticket is to remove the switch. This will simplify the code for this PR:

• Get server time in enhance methods and prop drill to DateTime #14660