Partial ungroup() is broken

[DavisVaughan]

In #6355, accidentally broken when moving from vars_select() to eval_select(), because vars_select() returns a character vector and eval_select() returns an integer vector

7c28098#diff-1ec33e14b938e61e20e0bef01b54aa084a603bfcbf3449c84535293f0f6ca9a5R154

Breaks MetAlyzer, found in #6262.

library(dplyr)

df <- tibble(g = 1)
gdf <- group_by(df, g)

gdf
#> # A tibble: 1 × 1
#> # Groups:   g [1]
#>       g
#>   <dbl>
#> 1     1

# Should ungroup by `g`
ungroup(gdf, g)
#> # A tibble: 1 × 1
#> # Groups:   g [1]
#>       g
#>   <dbl>
#> 1     1

^{Created on 2022-12-14 with reprex v2.0.2.9000}