linearGradient renders no data when series data is constant

[Willyham]

When a series has constant values for the y-axis, eg. [{x:1, y:100}, {x:2, y:100}, ... {x:n, y:100}], gradients do not render at all. I would expect that the series is rendered entirely in the 0% stop colour defined in the gradient.

See this CodeSandbox link for repo: https://codesandbox.io/s/wizardly-brahmagupta-p3gty?file=/src/App.js And live demo: https://p3gty.csb.app/