Let arr.reshape use Expr as inputs instead of just python tuple

[deanm0000]

Description

Suppose I have

zz=pl.DataFrame({'a':
    [[1,2],[2,3],[3,4]]}, schema={'a':pl.Array(pl.Int8,2)}
    )

Let's say I want to add 3, I can do

zz.select((pl.col('a').explode()+3).reshape((3,2)))

or even

zz.select((pl.col('a').explode()+3).reshape((zz.shape[0],zz.schema['a'].shape[0])))

but it'd be nice if we could do

zz.select((pl.col('a').explode()+3).reshape(pl.len(),pl.col('a').arr.to_list().list.len()))

"nice" here is relative since we still have to turn it into a list to get its original width in an expression.

Note: I just used adding a scaler as a simple example, I know that that'll work natively soon.