That URL parameter doesn't work on PBI SSRS only on the PBI cloud service. Its been on the backlog of things the dev team say is coming for a while now. Am surprised it didn't turn up in the Aug2018 release but am sure there were other priorities.
There is a surprisingly shabby workaround that does seem to work here.
So, using the new preview filter features, in order to hide the filter pane I need to:
open my Report in "Power BI Desktop"
hide the filter pane, as described on the link, and save
then open that report in "Power Bi Desktop (January 2019)" , current version for PBI Report Server and save the report again
Then I can upload it to PBI Report server
This worked for me, I can now embed a report without the filter pane. However all these steps to achieve it, feels like I'm missing something. Does anyone have any suggestions on how to do this the right way?
I can't get the filterPaneEnabled=false to work so this feature is welcomed