Disabled ACR admin user by default (#2253)

With the change from #2245 we are now able to disable the ACR admin user by default.

This is a security best practice. More information available in azure docs

Author: wbreza

templates/common/infra/bicep/core/host/container-registry.bicep

@@ -2,7 +2,7 @@ param name string
 param location string = resourceGroup().location
 param tags object = {}
 
-param adminUserEnabled bool = true
+param adminUserEnabled bool = false
 param anonymousPullEnabled bool = false
 param dataEndpointEnabled bool = false
 param encryption object = {