forge: set a title to the commit gadget field

This fixes the testNamingConvention failure:

    AssertionError: erp5_vcs/BusinessTemplate_viewVcsStatusDialog : your_commit_json : can't be empty

Since this field is in bottom group, the label is not rendered, so it's
not needed to hide field name with some TALES.

bt5/erp5_forge/SkinTemplateItem/portal_skins/erp5_vcs/BusinessTemplate_viewVcsStatusDialog/your_commit_json.xml

@@ -72,9 +72,7 @@
                 </item>
                 <item>
                     <key> <string>title</string> </key>
-                    <value>
-                      <persistent> <string encoding="base64">AAAAAAAAAAM=</string> </persistent>
-                    </value>
+                    <value> <string></string> </value>
                 </item>
                 <item>
                     <key> <string>validator_field_id</string> </key>
@@ -140,17 +138,4 @@
       </dictionary>
     </pickle>
   </record>
-  <record id="3" aka="AAAAAAAAAAM=">
-    <pickle>
-      <global name="TALESMethod" module="Products.Formulator.TALESField"/>
-    </pickle>
-    <pickle>
-      <dictionary>
-        <item>
-            <key> <string>_text</string> </key>
-            <value> <string>string:</string> </value>
-        </item>
-      </dictionary>
-    </pickle>
-  </record>
 </ZopeData>