Incorrect location header returned by Trigger invoice group run endpoint

[reshmabidikar]

The Trigger invoice group run endpoint returns the group id in the location header. However, the client libraries (Java, PHP, etc.) are unable to obtain the invoice group using this location header as the Retrieve invoice group endpoint also requires the accountId to be specified as a query parameter. Thus, the code needs to be fixed here to also return the accountId in the location header.