erp5_trade: max line limite to 20000

user sometimes copy&paste from xlxs more than 1000000 lines(most datas are just empty)

bt5/erp5_trade/SkinTemplateItem/portal_skins/erp5_trade/Base_viewTradeFieldLibrary/my_view_mode_description.xml

@@ -9,7 +9,9 @@
         <item>
             <key> <string>delegated_list</string> </key>
             <value>
-              <list/>
+              <list>
+                <string>max_lines</string>
+              </list>
             </value>
         </item>
         <item>
@@ -77,6 +79,10 @@
                     <key> <string>form_id</string> </key>
                     <value> <string>Base_viewFieldLibrary</string> </value>
                 </item>
+                <item>
+                    <key> <string>max_lines</string> </key>
+                    <value> <int>20000</int> </value>
+                </item>
                 <item>
                     <key> <string>target</string> </key>
                     <value> <string>Click to edit the target</string> </value>