tdf#89852 on Windows do not decode the filename for email subject

... because MAPISendMail does not accept Unicode

Change-Id: Id48a41d1cf25d1a991b0f83fd5daa1a65896e958
(cherry picked from commit 77ff5162)
Reviewed-on: https://gerrit.libreoffice.org/19830Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
(cherry picked from commit cf4b042c)

sfx2/source/dialog/mailmodel.cxx

@@ -828,7 +828,11 @@ SfxMailModel::SendMailResult SfxMailModel::Send( const css::uno::Reference< css:
                     OUString subject(
                         url.getBase(
                             INetURLObject::LAST_SEGMENT, false,
+#ifdef WNT
+                            INetURLObject::NO_DECODE)); // MAPISendMail does not accept Unicode
+#else
                             INetURLObject::DECODE_WITH_CHARSET));
+#endif
                     if (subject.isEmpty()) {
                         subject = maAttachedDocuments[0];
                     }