fixup! erp5_trade_ui_test: add functional tests on the use of "price per slice"

bt5/erp5_trade_ui_test/PathTemplateItem/portal_tests/trade_zuite/testInternalSupplyLinePricePerSlice.zpt

@@ -87,8 +87,7 @@ Test quantity steps for price on internal supply line
 <tr>
   <td>type</td>
   <td>field_my_quantity_step_list</td>
-  <td>11
-21</td>
+  <td>11<br />21</td>
 </tr>
 <tr>
   <td>clickAndWait</td>

bt5/erp5_trade_ui_test/PathTemplateItem/portal_tests/trade_zuite/testPurchaseSupplyLinePricePerSlice.zpt

@@ -87,8 +87,7 @@ Test quantity steps for price on purchase supply line
 <tr>
   <td>type</td>
   <td>field_my_quantity_step_list</td>
-  <td>11
-21</td>
+  <td>11<br />21</td>
 </tr>
 <tr>
   <td>clickAndWait</td>

bt5/erp5_trade_ui_test/PathTemplateItem/portal_tests/trade_zuite/testSaleSupplyLinePricePerSlice.zpt

@@ -86,8 +86,7 @@ Test quantity steps for price on sale supply line
 <tr>
   <td>type</td>
   <td>field_my_quantity_step_list</td>
-  <td>11
-21</td>
+  <td>11<br />21</td>
 </tr>
 <tr>
   <td>clickAndWait</td>