This is necessary to not get IWYU warnings or build errors
where SFX_DECL_INTERFACE is used

Also remove an earlier workaround in sd

Change-Id: I4cc86f7ad0c83aeaae225ee05af34fa49ba67e73
Reviewed-on: https://gerrit.libreoffice.org/55955
Tested-by: Jenkins
Reviewed-by: Jochen Nitschke <j.nitschke+logerrit@ok.de>