Quiet linear svm models

[topepo]

Related to tidymodels/tune#1039

Linear SVMs have no kernel parameters but loudly complain that none were specified. Adding kpar = list() appears to shush it.

Before

library(parsnip)
library(modeldata)
#> 
#> Attaching package: 'modeldata'
#> The following object is masked from 'package:datasets':
#> 
#>     penguins

res <- 
  svm_linear(mode = "classification", engine = "kernlab") |> 
  fit(Class ~ ., data = two_class_dat)
#>  Setting default kernel parameters

^{Created on 2025-07-15 with reprex v2.1.1}

After

library(parsnip)
library(modeldata)
#> 
#> Attaching package: 'modeldata'
#> The following object is masked from 'package:datasets':
#> 
#>     penguins

res <- 
  svm_linear(mode = "classification", engine = "kernlab") |> 
  fit(Class ~ ., data = two_class_dat)

^{Created on 2025-07-15 with reprex v2.1.1}