feat!: provide key columns as scalars (vs. vectors) to RollingFormula

[deephaven-internal]

This issue was auto-generated

PR: deephaven/deephaven-core#6375
Author: lbooker42

Original PR Body

Example:

NOTE: Sym is a key column and is constant for each bucket. It is presented to the UDF as a string (not a vector). intCol / longCol are vectors containing the window data.

t_out = t.updateBy(UpdateByOperation.RollingFormula(prevTicks, postTicks,
        "out_val=sum(intCol) - max(longCol) + (Sym == null ? 0 : Sym.length())"), "Sym");