NetcodeServerRateManager spams warning when set to Sleep

Steps to reproduce:

1.  Create a NetCodeConfig in NetcodeSamples
2.  Set `ClientServerTickRate.targetFrameRateMode` to Sleep
3.  Play any sample (e.g. NetCube)

Actual results: 
Console gets spammed with `Testing if will update when TargetFrameRateMode is set to Sleep`

Expected results: 
No warning is logged to the console

Reproducible with versions: 
1.9.0

Not reproducible with versions: 
1.8.0

Can’t test with versions: 

Tested on (OS): 
Mac

Notes:
Reported by a user here: https://discussions.unity.com/t/log-get-spammed-testing-if-will-update-when-targetframeratemode-is-set-to-sleep/1689415

The PR that introduced this issue: [Internal link]