`lazy_dt()` doesn't respect grouping

[mgirlich]

The grouping information is lost after using lazy_dt()

library(dplyr, warn.conflicts = FALSE)
library(dtplyr, warn.conflicts = FALSE)

tibble(x = 1) %>% 
  group_by(x) %>% 
  lazy_dt()
#> Source: local data table [1 x 1]
#> Call:   `_DT1`
#> 
#>       x
#>   <dbl>
#> 1     1
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results

^{Created on 2021-03-02 by the reprex package (v1.0.0)}