`format` + `where` fails on a `DataFrame` with a `ColumnGroup`

[Allex-Nik]

When format with a where clause is applied to a DataFrame containing a ColumnGroup, if fails with an exception saying that the column mentioned in the where clause is not found.
The problem does not occur if the where clause is removed or if the ColumnGroup is ungrouped.

Here is an example:

val df = dataFrameOf("firstName", "lastName", "age")(
    "Alice", "Cooper", 15,
    "Bob", "Dylan", 45,
    "Charlie", "Daniels", 20,
)

val groupedName = df.group { firstName and lastName }.into("name")

// this works
df.format { all() }.where { age < 18 }.with { background(RgbColor(242, 210, 189)) and textColor(black) }

// this also works
groupedName.format { all() }.with { background(RgbColor(242, 210, 189)) and textColor(black) }

// this fails
groupedName.format { all() }.where { age < 18 }.with { background(RgbColor(242, 210, 189)) and textColor(black) }

The exception from the example is the following: java.lang.IllegalArgumentException: Column not found: 'age'.

A notebook with the example is attached below.

formatIssue.ipynb