AuthorDelegate: Add pointing hand cursor to indicate you can tap

It's not immediately obvious that you can press on this static text to
bring up the user's details. This isn't a problem with the avatar - for
example - because it has a pointing hand cursor. Let's do the same here.

(cherry picked from commit 0ccfe7d991)

src/timeline/AuthorComponent.qml

@@ -43,7 +43,6 @@ RowLayout {
 
     QQC2.AbstractButton {
         id: nameButton
-        Layout.fillWidth: true
         contentItem: QQC2.Label {
             text: root.author.disambiguatedName
             color: root.author.color
@@ -53,6 +52,10 @@ RowLayout {
         }
         Accessible.name: contentItem.text
         onClicked: RoomManager.resolveResource(root.author.uri)
+
+        HoverHandler {
+            cursorShape: Qt.PointingHandCursor
+        }
     }
     QQC2.Label {
         id: timeLabel