As you can see, I'm not specifying a value for the "showTabs" property in the request. According to the docs, the default value is false (but I'd rather there not be a value sent to the server for that at all, if possible).
What I've found is that if I'm given the "Set Permissions" capability on the workbook, I can perform the above request successfully.
Is there any way around this without having to have the Set Permissions capability? Or is there another API I can use to move a workbook to another project?