Resolves fdo#84283: Export to PDF with footnotes in tables crash

Don't crash when there's no rectangles

Change-Id: I7e713025cacd449f708176254e05d40c0929577f
Reviewed-on: https://gerrit.libreoffice.org/11634Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sw/source/core/text/EnhancedPDFExportHelper.cxx

@@ -1934,11 +1934,15 @@ void SwEnhancedPDFExportHelper::EnhancedPDFExport()
             SwRects aTmp;
             aTmp.insert( aTmp.begin(), mrSh.SwCrsrShell::_GetCrsr()->begin(), mrSh.SwCrsrShell::_GetCrsr()->end() );
             OSL_ENSURE( !aTmp.empty(), "Enhanced pdf export - rectangles are missing" );
-            const SwRect aLinkRect( aTmp[ 0 ] );
 
             mrSh._GetCrsr()->RestoreSavePos();
             mrSh.SwCrsrShell::ClearMark();
 
+            if (aTmp.empty())
+                continue;
+
+            const SwRect aLinkRect( aTmp[ 0 ] );
+
             // Goto footnote text:
             if ( mrSh.GotoFtnTxt() )
             {