This issue is not reproducible with the dataset provided. The timeout for validating the network topology is ten minutes, which aligns with the default service usage timeout. Synchronous validate operations run from the Validate command on the Utility Network tab will result in a timeout at ten minutes with an error indicating the reason for the failure.
The Validate Network Topology geoprocessing tool takes advantage of asynchronous processing which uses the Utility Network tools geoprocessing service. It has a longer timeout setting and is reserved for utility network geoprocessing tasks. Errors returned from the geoprocessing framework have also been improved in ArcGIS Pro releases since version 2.2 and presents a similar timeout error as seen when using the Validate command in the user interface.