[9.x] Fix ProhibitedIf docblock and constructor (#42964)

This applies the same fixes to ProhibitIf as ExcludeIf.
- Missing @throws declaration in docblock: laravel/framework#41729
- Enforces a boolean in the constructor: laravel/framework#41931 laravel/framework#41969

Also fixes the ExcludeIf @var docblock to match as a \Closure

Rules/ExcludeIf.php

@@ -10,7 +10,7 @@ class ExcludeIf
     /**
      * The condition that validates the attribute.
      *
-     * @var callable|bool
+     * @var \Closure|bool
      */
     public $condition;
 

Rules/ProhibitedIf.php

@@ -2,26 +2,29 @@
 
 namespace Illuminate\Validation\Rules;
 
+use Closure;
 use InvalidArgumentException;
 
 class ProhibitedIf
 {
     /**
      * The condition that validates the attribute.
      *
-     * @var callable|bool
+     * @var \Closure|bool
      */
     public $condition;
 
     /**
      * Create a new prohibited validation rule based on a condition.
      *
-     * @param  callable|bool  $condition
+     * @param  \Closure|bool  $condition
      * @return void
+     *
+     * @throws \InvalidArgumentException
      */
     public function __construct($condition)
     {
-        if (! is_string($condition)) {
+        if ($condition instanceof Closure || is_bool($condition)) {
             $this->condition = $condition;
         } else {
             throw new InvalidArgumentException('The provided condition must be a callable or boolean.');