This modification aim to allow users to set value via textMapping and
these values to be used in background coloring as it text coloring.

This pull request closes #8404, but doesn't agree with #9012.
The issue #9012 consider that no coloring output should be put when
there is no data. I partially agree with this as I explicitely setted a
value in the textMapping I obviously want to treat `N/A` as a number.

`data.valueFormatted` contain the stringified version of `data.value`

If `Number()` cannot convert a string into a number a `NaN` value is
returned. So the code is still valid if the inputted value in
`data.valueFormatted` is not a number.