[FIX] mrp: field resource_type in mrp.workcenter tree view

The field resource_type in mrp.workcenter tree view must be invisible because
this field was not available in the form view before f9f4bba2

Adding resource_type in the form view had no business case.

opw:698183

addons/mrp/views/mrp_workcenter_views.xml

@@ -39,7 +39,7 @@
                     <field name="sequence" widget="handle"/>
                     <field name="code"/>
                     <field name="name"/>
-                    <field name="resource_type"/>
+                    <field name="resource_type" invisible="1"/>
                     <field name="company_id" groups="base.group_multi_company"/>
                     <field name="active" invisible="1"/>
                 </tree>
@@ -287,7 +287,6 @@
                         <group>
                             <group>
                                 <field name="name" string="Work Center Name"/>
-                                <field name="resource_type"/>
                             </group>
                             <group>
                                 <field name="code"/>