Port most Avatar usage to new KirigamiAddons Avatar

(cherry picked from commit 847f41e1ad)

src/qml/Component/Timeline/StateComponent.qml

@@ -6,6 +6,7 @@ import QtQuick.Controls 2.15 as QQC2
 import QtQuick.Layouts 1.15
 
 import org.kde.kirigami 2.15 as Kirigami
+import org.kde.kirigamiaddons.labs.components 1.0 as KirigamiComponents
 
 import org.kde.neochat 1.0
 
@@ -21,14 +22,23 @@ RowLayout {
 
     implicitHeight: Math.max(label.contentHeight, stateAvatar.implicitHeight)
 
-    Kirigami.Avatar {
+    KirigamiComponents.Avatar {
         id: stateAvatar
+
         Layout.preferredWidth: Kirigami.Units.iconSizes.small
         Layout.preferredHeight: Kirigami.Units.iconSizes.small
 
         name: root.name
         color: root.color
 
+        Rectangle {
+            radius: height
+            height: 4
+            width: 4
+            color: root.color
+            anchors.centerIn: parent
+        }
+
         MouseArea {
             anchors.fill: parent
             cursorShape: Qt.PointingHandCursor