Add workaround for delegate stuck transition bug

Sometimes and randomly, a HListView/HGridView delegate's
add/populate transition will stop before completion.

This especially happens on startup when loading a large room list,
one room might get stuck and left tiny or invisible, despite its
normal space still being taken.

src/gui/Base/DelegateTransitionFixer.qml

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+
+import QtQuick 2.12
+
+Timer {
+    // Sometimes and randomly, a HListView/HGridView delegate's add/populate
+    // Transition will stop too early, leaving a stuck invisible or tiny item.
+    // This is a workaround for this Qt bug happening despite the neccessary
+    // Transition precautions from the docs being applied.
+
+    property Item delegate: parent
+
+    readonly property HNumberAnimation opacityFixer: HNumberAnimation {
+        target: delegate
+        property: "opacity"
+        from: delegate.opacity
+        to: 1
+    }
+
+    readonly property HNumberAnimation scaleFixer: HNumberAnimation {
+        target: delegate
+        property: "scale"
+        from: delegate.scale
+        to: 1
+    }
+
+
+    interval: theme.animationDuration * 2
+    running: true
+    onTriggered: {
+        // if (delegate.opacity < 1 || delegate.scale < 1) print(delegate)
+        if (delegate.opacity < 1) opacityFixer.start()
+        if (delegate.scale < 1) scaleFixer.start()
+    }
+}

src/gui/MainPane/AccountDelegate.qml

@@ -243,4 +243,6 @@ HTile {
         sequences: window.settings.keys.togglePresenceOffline
         onActivated: account.togglePresence("offline")
     }
+
+    DelegateTransitionFixer {}
 }

src/gui/MainPane/RoomDelegate.qml

@@ -207,6 +207,8 @@ HTile {
         if (loadEventsFutureId) py.cancelCoro(loadEventsFutureId)
     }
 
+    DelegateTransitionFixer {}
+
     Timer {
         interval: 1000
         triggeredOnStart: true

src/gui/Pages/AccountSettings/DeviceDelegate.qml

@@ -173,4 +173,6 @@ HTile {
     }
 
     onLeftClicked: checkBox.clicked()
+
+    DelegateTransitionFixer {}
 }

src/gui/Pages/AddAccount/ServerDelegate.qml

@@ -92,4 +92,6 @@ HTile {
     }
 
     Behavior on contentOpacity { HNumberAnimation {} }
+
+    DelegateTransitionFixer {}
 }

src/gui/Pages/Chat/AutoCompletion/CompletableUserDelegate.qml

@@ -49,4 +49,6 @@ HTile {
             Behavior on color { HColorAnimation {} }
         }
     }
+
+    DelegateTransitionFixer {}
 }

src/gui/Pages/Chat/FileTransfer/Transfer.qml

@@ -33,6 +33,8 @@ HColumnLayout {
 
     Behavior on height { HNumberAnimation {} }
 
+    DelegateTransitionFixer {}
+
     HRowLayout {
         HIcon {
             svgName: "uploading"

src/gui/Pages/Chat/RoomPane/MemberView/MemberDelegate.qml

@@ -171,4 +171,6 @@ HTile {
         value: (roomPane.minimumSize - avatar.width) / 2
         when: avatar && roomPane.width < avatar.width + theme.spacing * 2
     }
+
+    DelegateTransitionFixer {}
 }

src/gui/Pages/Chat/RoomPane/MemberView/MemberDeviceDelegate.qml

@@ -64,4 +64,6 @@ HTile {
         )
         item.trustSet.connect(deviceTile.trustSet)
     }
+
+    DelegateTransitionFixer {}
 }

src/gui/Pages/Chat/Timeline/EventDelegate.qml

@@ -84,6 +84,8 @@ HColumnLayout {
 
     ListView.onRemove: eventList.uncheck(model.id)
 
+    DelegateTransitionFixer {}
+
     Item {
         Layout.fillWidth: true
         visible: model.event_type !== "RoomCreateEvent"