FR: "Radial" should have the same formula field like "bar"

[ste-fle]

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I'm currently using the sidebar to show CPU and RAM data of the raspberry HA is running on, but as compact as possible. CPU already comes in percent and therefore works great with the radial type, RAM "unfortunately" is provided with the used memory in MB and is displayed incorrectly. So instead, I used "bar" which has the ability to compute a different output using a formula - this should also be possible in the "radial" to compute percentage values.