How to disable the password strength meter script on reset password page?

Question

If you only want to hide the password strength meter, you could do so via CSS.

In your plugin

function login_stylesheet() {
    wp_enqueue_style( 'custom-login', plugins_url( 'login.css', __FILE__ ) );
}
add_action( 'login_enqueue_scripts', 'login_stylesheet' );

In login.css (hide box and change border-color of inputs)

body.login-action-rp #pass-strength-result {
    display: none;
}
body.login-action-rp #pass1,
body.login-action-rp #pass1-text {
    border-color: rgb(221,221,221) !important;
}

If you want to completely remove the script, you need to dequeue password-strength-meter as well as remove the dependancy that user-profile has on that.

add_action('login_enqueue_scripts', function(){
  wp_dequeue_script('password-strength-meter');
  wp_dequeue_script('user-profile');
  wp_deregister_script('user-profile');

  $suffix = SCRIPT_DEBUG ? '' : '.min';
  wp_enqueue_script( 'user-profile', "/wp-admin/js/user-profile$suffix.js", array( 'jquery', 'wp-util' ), false, 1 );
});

To be honest I didn’t check for full functionality, in my local example it all worked fine without the script.