Custom Welcome Widget in all themes

Hello,

I’m using a custom welcome widget. I have added the code to my themes function.php. I noticed that when I change the theme the welcome widget doesn’t appear – obviously as the active function.php file has changed. Is there a way to make the widget appear always no matter which theme is activated

<?php

// DASHBOARD WELCOME WIDGET

function register_raccoonbox_ohjauspaneeli_vimpain() {
 	global $wp_meta_boxes;

	wp_add_dashboard_widget(
		'raccoonbox_ohjauspaneeli_vimpain',
		'Tervetuloa mahtavalle sivullesi!',
		'raccoonbox_ohjauspaneeli_vimpain_display'
	);

 	$dashboard = $wp_meta_boxes['dashboard']['normal']['core'];

	$my_widget = array( 'raccoonbox_ohjauspaneeli_vimpain' => $dashboard['raccoonbox_ohjauspaneeli_vimpain'] );
 	unset( $dashboard['raccoonbox_ohjauspaneeli_vimpain'] );

 	$sorted_dashboard = array_merge( $my_widget, $dashboard );
 	$wp_meta_boxes['dashboard']['normal']['core'] = $sorted_dashboard;
}
add_action( 'wp_dashboard_setup', 'register_raccoonbox_ohjauspaneeli_vimpain' );

function raccoonbox_ohjauspaneeli_vimpain_display() {
	?>

  <a href="https://raccoonbox.com" target="_blank"><img src="https://raccoonbox.com/raccoonbox-img/RACCOONBOX-logo_200.png" alt="Raccoonbox logo" width="100px" height="100px"></a>

	<p>
	   Lorem
	</p>
	<p>
	   Lorem
	</p>

	<?php
}

// EDIT ADMIN FOOTER

add_filter('admin_footer_text', 'remove_footer_admin'); //change admin footer text
function remove_footer_admin () {
echo 'Kiitos kun valitsit <a href="https://raccoonbox.com">Raccoonboxin</a> | Muotoilija <a href="https://raccoonbox.com/muotoilijat">Konstantin Nikkari</a';
}

?>