I am using reporting services 2010 and get the following prompt when trying to access the reports:
If you just want to by pass the login prompt, you can modify the 'TargetServerURL' as it includes 'reportserver'. (It is like suffixing Controller with controller name in MVC)
Environment: Visual Studio 2008, Sql Server 2008
For me, it prompted when I set the 'TargetServerURL' to localhost/finreport. As mentioned in the below article, changing the 'TargetServerURL' to localhost/reportserver bypassed the login prompt.
For more info: https://docs.microsoft.com/en-us/sql/reporting-services/tools/reporting-services-login-dialog-box-ssrs