[renderjs_ui] Fix label rendering after moving css_class to field div

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_nojqm_css.css

@@ -1128,10 +1128,10 @@ div[data-gadget-scope='header'] .ui-header ul {
 .gadget-content .ui-field-contain > label {
   color: #777777;
 }
-.gadget-content .ui-field-contain > label.required {
+.gadget-content .required > .ui-field-contain > label {
   font-weight: bold;
 }
-.gadget-content .ui-field-contain > label.invisible {
+.gadget-content .invisible > .ui-field-contain > label {
   display: none;
 }
 @media only screen and (min-width: 45em) and (max-width: 85em), not screen and (max-width: 85em) {

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_nojqm_css.xml

@@ -242,7 +242,7 @@
             </item>
             <item>
                 <key> <string>serial</string> </key>
-                <value> <string>965.11760.24459.2133</string> </value>
+                <value> <string>965.12209.2660.49049</string> </value>
             </item>
             <item>
                 <key> <string>state</string> </key>
@@ -260,7 +260,7 @@
                     </tuple>
                     <state>
                       <tuple>
-                        <float>1517390712.66</float>
+                        <float>1517418109.55</float>
                         <string>UTC</string>
                       </tuple>
                     </state>

bt5/erp5_web_renderjs_ui/SkinTemplateItem/portal_skins/erp5_web_renderjs_ui/erp5css.less.txt

@@ -1307,17 +1307,19 @@ div[data-gadget-scope='header'] .ui-header {
     & > label {
       color: @grey;
 
+    }
+  }
+  //Label styling in required and "invisible" field
+  .required > .ui-field-contain > label {
     // backward-compatibility: support for ERP5 field class defined in formulator configuration
-      &.required {
     // inform user that the field is needed by contraint, but do not prevent him to save the value
     font-weight: bold;
   }
-      &.invisible {
+  .invisible > .ui-field-contain > label {
     // used to hide the label of a formbox
     display: none;
   }
-    }
-  }
+
 
   @media @tablet, @desktop {
     .ui-field-contain {