WithOnInterruptFunc should default to exiting the program

[panbanda]

A change was added in #507 which allowed for more graceful termination, however the default functionality does not properly exit.

package main

import (
	"fmt"

	"github.com/pterm/pterm"
)


func main() {
	list := []string{"hello", "world", "example"}

	selectedItem, _ := pterm.DefaultInteractiveSelect.
		WithDefaultText("Select an item").
		WithMaxHeight(20).
		WithOptions(list).
		Show()

	fmt.Println("selected item:", selectedItem)
}

Expected output when running Ctrl + C

$ go run main.go
Select an item [type to search]: 
> hello
  world
  example
exit status 1

Actual output:

$ go run main.go
Select an item [type to search]: 
> hello
  world
  example
selected item: hello