sw: fix invalid cast in SwEditWin::RequestHelp()

This results in a garbage OUString.

Change-Id: I03b8030a812d7016df5c29f1341749fbdedf1729
Reviewed-on: https://gerrit.libreoffice.org/61652
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>
(cherry picked from commit bf0276f0)
Reviewed-on: https://gerrit.libreoffice.org/61674Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
(cherry picked from commit 2c93c692)

sw/source/uibase/docvw/edtwin2.cxx

@@ -170,7 +170,7 @@ void SwEditWin::RequestHelp(const HelpEvent &rEvt)
 
             case IsAttrAtPos::InetAttr:
             {
-                sText = static_cast<const SfxStringItem*>(aContentAtPos.aFnd.pAttr)->GetValue();
+                sText = static_cast<const SwFormatINetFormat*>(aContentAtPos.aFnd.pAttr)->GetValue();
                 sText = URIHelper::removePassword( sText,
                                         INetURLObject::EncodeMechanism::WasEncoded,
                                            INetURLObject::DecodeMechanism::Unambiguous);