adding dynamic/multiple slug values in ‘option_none_value’

I am working on a wordpress website and i am little stuck into one situation, what i want is that to add multiple and dynamic slug values from job listing taxonomy, right now i have to manually insert the slug name into ‘option_none_value’ => ”, if no category is selected. I searched allot on google but didnt find any relevant solution.

wp_dropdown_categories( 
array(
    'show_option_none'   => 'All Job-types',
    'option_none_value'  => '',
    'value_field'       => 'slug',
    'taxonomy'          => 'job_listing_type',
    'name'              => 'search_type',
    'orderby'           => 'name',
    'class'             => 'select-on-home',
    'hierarchical'      => true,
    'hide_empty'        => true ,
    'show_option_all'   => esc_html__('','workscout'),
    'echo' => 0
)

);