Improve z-ordering of account avatar elements

Show presence orb in front of unread messages, which are shown in front
of the loading spinner overlays

src/gui/Base/HUserAvatar.qml

@@ -59,7 +59,7 @@ HAvatar {
         anchors.bottomMargin: -diameter / 2
         anchors.rightMargin: -diameter / 2
         opacity: theme.controls.presence.opacity
-        z: 100
+        z: 300
 
         property int diameter:
             window.settings.compactMode ?

src/gui/MainPane/AccountDelegate.qml

@@ -35,7 +35,7 @@ HTile {
 
             HLoader {
                 anchors.fill: parent
-                z: 9998
+                z: 100
                 opacity: model.connecting ? 1 : 0
                 active: opacity > 0
 
@@ -57,7 +57,7 @@ HTile {
                 id: totalMessageIndicator
                 anchors.right: parent.right
                 anchors.bottom: parent.bottom
-                z: 9999
+                z: 200
 
                 indicatorTheme:
                     theme.mainPane.accountBar.account.unreadIndicator