disable atomic compression when using trim

[moodymudskipper]

here the Petal.Width expression doesn't make sense:

constructive::construct(iris, opts_atomic(trim = 5, fill = "..."))
#> ! The code built by {constructive} could not be evaluated.
#> ! Due to error: '...' used in an incorrect context
#> data.frame(
#>   Sepal.Length = c(5.1, 4.9, 4.7, 4.6, 5, ...),
#>   Sepal.Width = c(3.5, 3, 3.2, 3.1, 3.6, ...),
#>   Petal.Length = c(1.4, 1.4, 1.3, 1.5, 1.4, ...),
#>   Petal.Width = rep(0.2, 5L, ...),
#>   Species = factor(rep(c("setosa", "versicolor", "virginica"), each = 50L))
#> )

We still want the compression to work on Species though