Add attributes to form element XSD definitions

Without this part of the configuration, children of <formElements> nodes
can not have their attributes (such as "class") configured.

Author: neillrobson

app/code/Magento/Ui/view/base/ui_component/etc/definition/boolean.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="componentBooleanSettings">

app/code/Magento/Ui/view/base/ui_component/etc/definition/checkbox.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="componentCheckboxSetting">

app/code/Magento/Ui/view/base/ui_component/etc/definition/checkboxset.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="componentCheckboxsetSettings">

app/code/Magento/Ui/view/base/ui_component/etc/definition/date.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="componentDateSettings">

app/code/Magento/Ui/view/base/ui_component/etc/definition/email.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="componentEmailSettings">

app/code/Magento/Ui/view/base/ui_component/etc/definition/file.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="componentFileSettings">

app/code/Magento/Ui/view/base/ui_component/etc/definition/hidden.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="hiddenSetting">

app/code/Magento/Ui/view/base/ui_component/etc/definition/input.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:complexType name="componentRange">

app/code/Magento/Ui/view/base/ui_component/etc/definition/multiselect.xsd

@@ -34,6 +34,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="componentMultiselectSettings">

app/code/Magento/Ui/view/base/ui_component/etc/definition/price.xsd

@@ -33,6 +33,7 @@
                 </xs:complexType>
             </xs:element>
         </xs:sequence>
+        <xs:attributeGroup ref="ui_element_attributes"/>
     </xs:complexType>
 
     <xs:group name="componentPriceSettings">