Update configure-monitoring.md

Adding a warning about Linux Dedicated and Elastic Premium.

Author: FinVamp1

articles/azure-functions/configure-monitoring.md

@@ -454,6 +454,7 @@ Update-AzFunctionAppSetting -Name MyAppName -ResourceGroupName MyResourceGroupNa
 
 > [!NOTE]
 > Overriding the `host.json` through changing app settings will restart your function app.
+> For Linux Elastic Premium and Dedicated plans it is not possible to use App Settings that contain a period, please continue to use the *host.json* file.
 
 ## Monitor function apps using Health check