fix: tooltip does not show the latest text

在这paintEvent中判断文本是否发生变化，如果变化了则调用DToolTip::setShowToolTip(this, false)重置状态，
确保Tooltip能显示最新的文本内容。为此在DLabelPrivate中增加了lastText成员变量用于记录上一次的文本。

Check if the text has changed in paintEvent. If it has changed, call DToolTip::setShowToolTip(this, false)
to reset the status, ensuring that the Tooltip displays the latest text content. To achieve this,
a lastText member variable was added to DLabelPrivate to record the previous text.

Log: fix tooltip does not show the latest text
Pms: BUG-300837

Author: yixinshark

src/widgets/dlabel.cpp

@@ -207,6 +207,12 @@ void DLabel::paintEvent(QPaintEvent *event)
                 palette.setBrush(foregroundRole(), DPaletteHelper::instance()->palette(this).brush(d_func()->color));
             }
 
+            if (!d->text.isEmpty() && d->text != d_func()->lastText) {
+                // clear flag when text changed, avoid tooltip don't show new text
+                DToolTip::setShowToolTip(this, false);
+            }
+            d_func()->lastText = d->text;
+
             QString text = d->text;
             if (elideMode() != Qt::ElideNone) {
                 const QFontMetrics fm(fontMetrics());

src/widgets/private/dlabel_p.h

@@ -27,6 +27,7 @@ class DLabelPrivate : public DTK_CORE_NAMESPACE::DObjectPrivate
 
     DPalette::ColorType color = DPalette::NoType;
     Qt::TextElideMode elideMode = Qt::ElideNone;
+    QString lastText;
 };
 
 DWIDGET_END_NAMESPACE