chore: update DTK dependency and fix icon display

Updated libdtk6declarative-dev dependency version from >= 6.0.19 to >>
6.7.33 to ensure compatibility with newer DTK features and bug fixes.
Added fillMode: Image.PreserveAspectFit to IconImage component in
IconItemDelegate.qml to prevent icon distortion and ensure proper aspect
ratio preservation when scaling icons.

chore: 更新 DTK 依赖并修复图标显示

将 libdtk6declarative-dev 依赖版本从 >= 6.0.19 更新为 >> 6.7.33，以确保
兼容新的 DTK 功能和错误修复。在 IconItemDelegate.qml 的 IconImage 组件中
添加 fillMode: Image.PreserveAspectFit，防止图标变形并确保缩放时保持正确
的宽高比。

PMS: BUG-301329

Author: mhduiy

debian/control

@@ -23,7 +23,7 @@ Build-Depends:
  libdtk6core-bin,
 # v-- provides DHiDPIHelper
  libdtk6gui-dev (>= 6.0.19),
- libdtk6declarative-dev (>= 6.0.19),
+ libdtk6declarative-dev (>> 6.7.33),
  libdde-shell-dev (>= 0.0.10),
  libappstreamqt-dev (>= 1.0.0)
 Standards-Version: 4.6.0

qml/IconItemDelegate.qml

@@ -1,4 +1,4 @@
-// SPDX-FileCopyrightText: 2023 UnionTech Software Technology Co., Ltd.
+// SPDX-FileCopyrightText: 2023 - 2026 UnionTech Software Technology Co., Ltd.
 //
 // SPDX-License-Identifier: GPL-3.0-or-later
 
@@ -178,6 +178,7 @@ Control {
                         scale: (parent.width / root.maxIconSize) * root.iconScaleFactor
                         palette: DTK.makeIconPalette(root.palette)
                         theme: ApplicationHelper.DarkType
+                        fillMode: Image.PreserveAspectFit
                     }
                 }
             }