Fix animated mask brushes painting as animated color image brushes
Recent changes in the internal representation of brushes caused animated mask brushes (PIPE_MASK) to draw as if they were animated image (PIPE_IMAGE) brushes. This fixes the issue.
Recent changes in the internal representation of brushes caused animated mask brushes (PIPE_MASK) to draw as if they were animated image (PIPE_IMAGE) brushes. This fixes the issue.