Timeline: Stretch date section sections across the whole ListView width

With paddings, it looked sort of glitched, especially in RTL layouts,
because messages from the top were highlighting all around the padded
section delegate.

src/qml/Component/Timeline/SectionDelegate.qml

@@ -19,6 +19,8 @@ QQC2.ItemDelegate {
     property int colorSet: Kirigami.Theme.Window
 
     topPadding: Kirigami.Units.largeSpacing
+    leftPadding: 0
+    rightPadding: 0
     bottomPadding: 0 // Note not 0 by default
 
     contentItem: ColumnLayout {

src/qml/Component/Timeline/TimelineContainer.qml

@@ -342,6 +342,8 @@ ColumnLayout {
     SectionDelegate {
         id: sectionDelegate
         Layout.fillWidth: true
+        // Fill ListView width without affecting size helper and the rest of components too much
+        Layout.rightMargin: root.parent ? root.width - root.parent.width : 0
         visible: root.showSection
         labelText: root.section
         colorSet: Config.compactLayout || root.alwaysMaxWidth ? Kirigami.Theme.View : Kirigami.Theme.Window

src/qml/Component/TimelineView.qml

@@ -36,7 +36,7 @@ QQC2.ScrollView {
         readonly property NeoChatRoom currentRoom: root.currentRoom
 
         readonly property int largestVisibleIndex: count > 0 ? indexAt(contentX + (width / 2), contentY + height - 1) : -1
-        readonly property var sectionBannerItem: contentHeight >= height ? itemAtIndex(sectionBannerIndex()) : undefined
+        readonly property Item sectionBannerItem: contentHeight >= height ? itemAtIndex(sectionBannerIndex()) : null
 
         // Spacing needs to be zero or the top sectionLabel overlay will be disrupted.
         // This is because itemAt returns null in the spaces.
@@ -108,13 +108,11 @@ QQC2.ScrollView {
         footer: SectionDelegate {
             id: sectionBanner
 
-            anchors.left: parent.left
-            anchors.leftMargin: messageListView.sectionBannerItem ? messageListView.sectionBannerItem.x : 0
-            anchors.right: parent.right
+            width: ListView.view ? ListView.view.width : 0
 
             maxWidth: Config.compactLayout ? messageListView.width : (messageListView.sectionBannerItem ? messageListView.sectionBannerItem.width - Kirigami.Units.largeSpacing * 2 : 0)
             z: 3
-            visible: !!messageListView.sectionBannerItem && messageListView.sectionBannerItem.ListView.section !== "" && !Config.blur
+            visible: messageListView.sectionBannerItem && messageListView.sectionBannerItem.ListView.section !== "" && !Config.blur
             labelText: messageListView.sectionBannerItem ? messageListView.sectionBannerItem.ListView.section : ""
             colorSet: Config.compactLayout ? Kirigami.Theme.View : Kirigami.Theme.Window
         }