fix: mask area exist two line for viewport

[18202781743]

mask's point maybe is extend if radius is float. it causes mask's aplha is zero in top2bottom and right2left line.

Issue: https://github.com/linuxdeepin/developer-center/issues/8313

[deepin-bot[bot]]

Doc Check bot :yellow_circle: some documents missing! File	Line	Symbol
src/private/dquickitemviewport_p.h	232	bool Dtk::Quick::DQuickItemViewportPrivate::needMaskNode
src/private/dquickrectangle_p_p.h	38	qreal Dtk::Quick::DQuickRectanglePrivate::radius
src/private/dquickrectangle_p_p.h	39	QColor Dtk::Quick::DQuickRectanglePrivate::color
src/private/dquickrectangle_p_p.h	40	DQuickRectangle::Corners Dtk::Quick::DQuickRectanglePrivate::corners
src/private/dquickrectangle_p_p.h	41	MaskTextureCache::TextureData Dtk::Quick::DQuickRectanglePrivate::maskTexture

[deepin-ci-robot]

deepin pr auto review

关键摘要:

• 将 float 类型更改为 int 可能会导致数值溢出，需要确认是否有足够的边界检查。
• qRound 函数的使用可能会导致小数点后的精度丢失，应确保这一改动是否符合业务逻辑需求。

是否建议立即修改:

• 是，需要确保类型更改后的边界条件和精度问题得到妥善处理。

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: 18202781743, zccrs

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