mainview: provide implicitWidth to contact search bar to elide place holder

Change-Id: I70c2fdbde8a17f0a3b123dbacfb3a07fcc89ca91

src/mainview/components/ContactPicker.qml

@@ -91,9 +91,11 @@ Popup {
                 Layout.alignment: Qt.AlignCenter
                 Layout.topMargin: 5
                 Layout.bottomMargin: 5
-                Layout.preferredWidth: contactPickerPopupRect.width - 10
+                Layout.preferredWidth: implicitWidth
                 Layout.preferredHeight: 35
 
+                implicitWidth: contactPickerPopupRect.width - 10
+
                 onContactSearchBarTextChanged: {
                     ContactAdapter.setSearchFilter(text)
                 }