Cannot resolve column from transitive schema in `AggregateGroupedDsl` with compiler plugin

[Jolanrensen]

To reproduce:

@DataSchema
interface A {
    val a: Int
}

@DataSchema
interface AB : A {
    val b: String
}

fun main() {
    val df = dataFrameOf("a", "b")(1, "2").cast<AB>()
        // fine
        df.a
        df.b
    
        df.groupBy { b }.aggregate {
            medianOf<_, String> { b } into "bMed" // works
            sumOf { a } into "aSum"  // cannot resolve a
        }
}