feat!: Add multi-column support to AggFormula

[deephaven-internal]

This issue was auto-generated

PR: deephaven/deephaven-core#6206
Author: lbooker42

Original PR Body

Python examples:

from deephaven import empty_table
from deephaven import agg

source = empty_table(20).update(
    ["X = i", "Y = 2 * i", "Z = 3 * i", "Letter = (X % 2 == 0) ? `A` : `B`"]
)

result = source.agg_by([
    agg.formula(formula="out_a=sqrt(5.0)"),
    agg.formula(formula="out_b=min(X)"),
    agg.formula(formula="out_c=min(X) + max(Y)"),
    agg.formula(formula="out_d=sum(X + Y + Z)"),
], by=["Letter"])

Groovy examples:

source = emptyTable(20).update("X = i", "Y = 2 * i", "Z = 3 * i", "Letter = (X % 2 == 0) ? `A` : `B`")

result = source.aggBy([
    AggFormula("out_a=sqrt(5.0)"),
    AggFormula("out_b=min(X)"),
    AggFormula("out_c=min(X) + max(Y)"),
    AggFormula("out_d=sum(X + Y + Z)"),
], "Letter")