fdo#74981: cutting nothing should do nothing, should fix field dupes

Change-Id: I8a8c9bfcd0943904384bb12b510a050ef8df9adf

sw/source/core/txtnode/ndtxt.cxx

@@ -1930,6 +1930,8 @@ OUString SwTxtNode::InsertText( const OUString & rStr, const SwIndex & rIdx,
 void SwTxtNode::CutText( SwTxtNode * const pDest,
             const SwIndex & rStart, const sal_Int32 nLen )
 {
+    if(nLen == 0)
+        return;
     if(pDest)
     {
         SwIndex aDestStt(pDest, pDest->GetTxt().getLength());