Don't list tab names twice

Summary:
The name (with a correct role) is already exported as a tab

By having the static text internally we get the name twice when we do a
flat review of the controls.

Reviewers: #plasma

Subscribers: plasma-devel, #frameworks

Tags: #plasma, #frameworks

Differential Revision: https://phabricator.kde.org/D7815

src/declarativeimports/plasmacomponents/qml/TabButton.qml

@@ -161,6 +161,7 @@ Item {
             id: label
 
             objectName: "label"
+            Accessible.ignored: true
 
             Layout.alignment: Qt.AlignVCenter | Qt.AlignHCenter
             Layout.preferredWidth: internal.portrait ? root.width : implicitWidth