Thread alignment

It doesn't make sense for a thread to be on the right or tinted when the local user started it as they contain messages from multiple users. So always make them align left and never tint them.

src/timeline/Bubble.qml

@@ -51,6 +51,11 @@ QQC2.Control {
      */
     required property var contentModel
 
+    /**
+     * @brief Whether the message in a thread.
+     */
+    required property bool isThreaded
+
     /**
      * @brief Whether the bubble background should be shown.
      */
@@ -134,7 +139,7 @@ QQC2.Control {
         visible: root.showBackground
         Kirigami.Theme.colorSet: Kirigami.Theme.View
         Kirigami.Theme.inherit: false
-        color: if (root.author.isLocalMember) {
+        color: if (root.author.isLocalMember && !root.isThreaded) {
             return Kirigami.ColorUtils.tintWithAlpha(Kirigami.Theme.backgroundColor, Kirigami.Theme.highlightColor, 0.15);
         } else if (root.showHighlight) {
             return Kirigami.Theme.positiveBackgroundColor;