new-call-box: Tweak the UI

- Fills horizontally now
- Make sure the "dial" and "backspace" button are still properly aligned
  by using HdyClamp with the keypads typical size (rougly 250)
- Remove unnecessary default values from the xml
  (f.e. "can-focus" on GtkEntry or GtkButton)

src/ui/new-call-box.ui

@@ -5,13 +5,11 @@
   <requires lib="libhandy" version="1.0"/>
   <template class="CallsNewCallBox" parent="GtkBox">
     <property name="can_focus">False</property>
-    <property name="halign">center</property>
     <property name="margin_bottom">16</property>
     <property name="margin_left">24</property>
     <property name="margin_right">24</property>
     <property name="margin_top">16</property>
     <property name="orientation">vertical</property>
-    <property name="valign">center</property>
     <property name="visible">True</property>
 
     <child>
@@ -19,6 +17,7 @@
         <property name="visible">True</property>
         <property name="selection-mode">none</property>
         <property name="margin-bottom">6</property>
+        <property name="halign">center</property>
         <child>
           <object class="HdyComboRow" id="origin_list">
             <property name="visible">True</property>
@@ -41,7 +40,6 @@
     <child>
       <object class="GtkEntry" id="keypad_entry">
         <property name="visible" bind-source="CallsNewCallBox" bind-property="numeric-input-only" bind-flags="sync-create"/>
-        <property name="can_focus">True</property>
         <property name="hexpand">True</property>
         <property name="xalign">0.5</property>
         <style>
@@ -64,6 +62,10 @@
         <property name="fill">True</property>
       </packing>
     </child>
+    <child>
+      <object class="HdyClamp">
+        <property name="visible">True</property>
+        <property name="maximum-size">250</property>
         <child>
       <object class="GtkBox">
         <property name="visible" bind-source="CallsNewCallBox" bind-property="numeric-input-only" bind-flags="sync-create"/>
@@ -94,15 +96,10 @@
               </object>
             </child>
           </object>
-          <packing>
-            <property name="expand">False</property>
-            <property name="fill">True</property>
-          </packing>
         </child>
         <child>
           <object class="GtkButton" id="backspace">
             <property name="always_show_image">True</property>
-            <property name="can_focus">True</property>
             <property name="visible">True</property>
             <property name="focus-on-click">False</property>
             <property name="margin_right">15</property>
@@ -130,6 +127,8 @@
         </child>
       </object>
         </child>
+      </object>
+    </child>
 
     <child>
       <object class="GtkListBox" id="result_list">