File Size View: Fix KProtocolInfoFactory assert

konqueror: ASSERT: "!protocol.isEmpty()" in file kio/src/core/kprotocolinfofactory.cpp, line 72

#4 0x00007ffff621f480 in KProtocolInfoFactory::findProtocol (this=<optimized out>, protocol=...)

at kio/src/core/kprotocolinfofactory.cpp:72

#5 0x00007ffff621a15f in KProtocolInfo::protocolClass (_protocol=...)

at kio/src/core/kprotocolinfo.cpp:331

#6 0x00007ffff62112bd in KUrlAuthorized::authorizeUrlAction (action=..., baseURL=..., destURL=...)

at kio/src/core/kurlauthorized.cpp:40

#7 0x00007fffcd0ae72d in FSView::setPath (this=this@entry=0x5555569a79d0, p=...)

at konqueror/plugins/fsview/fsview.cpp:146

#8 0x00007fffcd096bae in FSViewPart::openUrl (this=0x555556a39e80, url=...)

at konqueror/plugins/fsview/fsview_part.cpp:325