Main functions doesn't do any input checking on `data` argument

sooo, there isn't much input checking for some of the main functions here in {rsample}, to the point of bootstraps(bootstraps) not returning an error 😬

bootstraps

library(rsample)

mat_cars <- as.matrix(mtcars)

bootstraps(mat_cars, times = 2)
#> # Bootstrap sampling 
#> # A tibble: 2 × 2
#>   splits          id        
#>   <list>          <chr>     
#> 1 <split [32/11]> Bootstrap1
#> 2 <split [32/11]> Bootstrap2

bootstraps(1:10, times = 2)
#> # Bootstrap sampling 
#> # A tibble: 0 × 2
#> # ℹ 2 variables: splits <list>, id <chr>

bootstraps(NULL)
#> # Bootstrap sampling 
#> # A tibble: 0 × 2
#> # ℹ 2 variables: splits <list>, id <chr>

bootstraps(lm(mpg ~ disp, data = mtcars))
#> # Bootstrap sampling 
#> # A tibble: 0 × 2
#> # ℹ 2 variables: splits <list>, id <chr>

vfold_cv

library(rsample)

mat_cars <- as.matrix(mtcars)

vfold_cv(mat_cars)
#> #  10-fold cross-validation 
#> # A tibble: 10 × 2
#>    splits         id    
#>    <list>         <chr> 
#>  1 <split [28/4]> Fold01
#>  2 <split [28/4]> Fold02
#>  3 <split [29/3]> Fold03
#>  4 <split [29/3]> Fold04
#>  5 <split [29/3]> Fold05
#>  6 <split [29/3]> Fold06
#>  7 <split [29/3]> Fold07
#>  8 <split [29/3]> Fold08
#>  9 <split [29/3]> Fold09
#> 10 <split [29/3]> Fold10

vfold_cv(1:10)
#> Error in if (v > max_v) {: argument is of length zero

vfold_cv(NULL)
#> Error in if (v > max_v) {: argument is of length zero

vfold_cv(lm(mpg ~ disp, data = mtcars))
#> Error in if (v > max_v) {: argument is of length zero

Start by reproducing the reported cases for the bootstraps and vfold_cv entry points with the invalid data values shown in the issue. Review how these functions currently handle those inputs and add input checking so invalid data produces an appropriate error rather than an empty result or an internal error; add tests for the examples.