sync: from linuxdeepin/qt5platform-plugins

[deepin-ci-robot]

Synchronize source files from linuxdeepin/qt5platform-plugins.

Source-pull-request: linuxdeepin/qt5platform-plugins#252

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[deepin-bot]

TAG Bot

New tag: 6.0.19
DISTRIBUTION: unstable
Suggest: synchronizing this PR through rebase #45

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 在DNoTitlebarWindowHelper::DNoTitlebarWindowHelper构造函数中，g_pressPoint.remove(this);可能会导致未处理的初始化问题，如果this已经在g_pressPoint中存在，则调用remove会失败。
• 在DNoTitlebarWindowHelper::windowEvent函数中，g_pressPoint[this]的赋值操作应该在if语句块之外，以避免潜在的未初始化问题。
• QPointF delta = me->globalPos() - g_pressPoint[this];计算了鼠标移动距离，但没有考虑到鼠标移动的累积效应，可能会导致在较短距离下误判移动事件。
• if (delta.manhattanLength() < QGuiApplication::styleHints()->startDragDistance())中的QGuiApplication::styleHints()->startDragDistance()应该使用QApplication::startDragDistance()，因为QGuiApplication在Qt 6中已经被移除。
• self->isEnableSystemMove(winId)函数调用可能需要检查是否为有效的窗口ID，以确保安全性。

是否建议立即修改:
是