Revert "frontend: warm default repo cache before serving traffic (#21238)"
Created by: tsenart
This reverts commit 0d0fa73e6237d6a66db2ee9dac9846dc213e0a29 which isn't needed anymore after #21835
Created by: tsenart
This reverts commit 0d0fa73e6237d6a66db2ee9dac9846dc213e0a29 which isn't needed anymore after #21835