[ChangeLog][QtGui][QColor] The constructors from string-ish type, as
well as the setNamedColor() and isValidColor() functions, have been
deprecated effective Qt 6.6 in favor of fromString() and
isValidColorName(), resp.
Fixes: QTBUG-101389
Change-Id: I002646bd48c1e4340dc6842fd136fc9f35bb9b61
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>