coverity#1416667 Unchecked dynamic_cast

Change-Id: I1df3f13c47a021bad7c5b5ab7d5804dc70f091c8
Reviewed-on: https://gerrit.libreoffice.org/41558Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/qa/extras/ww8export/ww8export2.cxx

@@ -62,6 +62,7 @@ DECLARE_WW8EXPORT_TEST(testTdf55427_footnote2endnote, "tdf55427_footnote2endnote
     CPPUNIT_ASSERT_EQUAL_MESSAGE( "Endnote style is cyan3 color", sal_Int32(0x2BD0D2), getProperty< sal_Int32 >(xPageStyle, "CharColor") );
 
     SwXTextDocument* pTextDoc = dynamic_cast<SwXTextDocument*>(mxComponent.get());
+    CPPUNIT_ASSERT(pTextDoc);
     SwDoc* pDoc = pTextDoc->GetDocShell()->GetDoc();
     // The footnote numbering type of ARABIC will not transfer over when those footnotes are converted to endnotes.
     CPPUNIT_ASSERT_EQUAL_MESSAGE( "Footnote numbering type", SVX_NUM_ARABIC, pDoc->GetFootnoteInfo().aFormat.GetNumberingType() );