FIX(a11y): Make AccessibleQGroupBox not read empty table cells

An AccessibleQGroupBox will try to compose an accessible description
based on the layout of labels within.
If a grid-layout is used, we read every row+column combination and
the corresponding grid cell content.

Previously, the AccessibleQGroup box would read row+column even if
there was not label in the actual cell, leading to unnecessary
text. (e.g. when using a sub headline)

This commit adds a check to skip a row+colum combination when
there is no label in the cell.

src/mumble/widgets/AccessibleQGroupBox.cpp

@@ -27,6 +27,11 @@ QString AccessibleQGroupBox::textAtPosition(QGridLayout *gridLayout, int y, int
 		return "";
 	}
 
+	QString accessibleName = label->accessibleName();
+	if (!accessibleName.isEmpty()) {
+		return accessibleName;
+	}
+
 	QString content = Mumble::Accessibility::removeHTMLTags(label->text());
 	if (content.trimmed().isEmpty()) {
 		content = tr("empty");
@@ -47,11 +52,14 @@ void AccessibleQGroupBox::updateAccessibleText() {
 		for (int y = tableMode ? 1 : 0; y < gridLayout->rowCount(); y++) {
 			for (int x = tableMode ? 1 : 0; x < gridLayout->columnCount(); x++) {
 				if (tableMode) {
-					text += textAtPosition(gridLayout, y, 0);
-					text += " ";
-					text += textAtPosition(gridLayout, 0, x);
-					text += ", ";
-					text += textAtPosition(gridLayout, y, x);
+					QString cellContent = textAtPosition(gridLayout, y, x);
+					if (!cellContent.isEmpty()) {
+						text += textAtPosition(gridLayout, y, 0);
+						text += " ";
+						text += textAtPosition(gridLayout, 0, x);
+						text += ", ";
+						text += cellContent;
+					}
 				} else {
 					text += textAtPosition(gridLayout, y, x);
 				}