Adapt the testpopover example

Drop all all explicit role setting from the testpopover example.

tests/popover2.ui

@@ -69,7 +69,6 @@
       <object class="GtkModelButton">
         <property name="visible">True</property>
         <property name="action-name">top.action2</property>
-        <property name="role">check</property>
         <property name="text">Toggle</property>
       </object>
     </child>
@@ -77,7 +76,6 @@
       <object class="GtkModelButton">
         <property name="visible">True</property>
         <property name="action-name">top.action2a</property>
-        <property name="role">check</property>
         <property name="text">Another Toggle</property>
       </object>
     </child>
@@ -112,7 +110,6 @@
         <property name="visible">True</property>
         <property name="action-name">top.action3</property>
         <property name="action-target">'three'</property>
-        <property name="role">radio</property>
         <property name="text">Radio 1</property>
       </object>
     </child>
@@ -121,7 +118,6 @@
         <property name="visible">True</property>
         <property name="action-name">top.action3</property>
         <property name="action-target">'four'</property>
-        <property name="role">radio</property>
         <property name="text">Radio 2</property>
       </object>
     </child>
@@ -266,7 +262,6 @@
             <property name="text">List</property>
             <property name="action-name">top.set-view</property>
             <property name="action-target">'list'</property>
-            <property name="role">radio</property>
             <property name="iconic">True</property>
             <property name="centered">True</property>
             <property name="icon">icon-list</property>
@@ -281,7 +276,6 @@
             <property name="text">Grid</property>
             <property name="action-name">top.set-view</property>
             <property name="action-target">'grid'</property>
-            <property name="role">radio</property>
             <property name="iconic">True</property>
             <property name="centered">True</property>
             <property name="icon">icon-grid</property>
@@ -358,7 +352,6 @@
             <property name="visible">True</property>
             <property name="text">Bold</property>
             <property name="action-name">top.bold</property>
-            <property name="role">check</property>
             <property name="iconic">True</property>
             <property name="centered">True</property>
           </object>
@@ -371,7 +364,6 @@
             <property name="visible">True</property>
             <property name="text">Italic</property>
             <property name="action-name">top.italic</property>
-            <property name="role">check</property>
             <property name="iconic">True</property>
             <property name="centered">True</property>
             <property name="icon">icon-italic</property>
@@ -385,7 +377,6 @@
             <property name="visible">True</property>
             <property name="text">Strikethrough</property>
             <property name="action-name">top.strikethrough</property>
-            <property name="role">check</property>
             <property name="iconic">True</property>
             <property name="centered">True</property>
             <property name="icon">icon-strikethrough</property>
@@ -399,7 +390,6 @@
             <property name="visible">True</property>
             <property name="text">Underline</property>
             <property name="action-name">top.underline</property>
-            <property name="role">check</property>
             <property name="iconic">True</property>
             <property name="centered">True</property>
             <property name="icon">icon-underline</property>