Added a helper for testing the From address from a Mailable. (#18790)

Author: MrAtiebatie

src/Illuminate/Mail/Mailable.php

@@ -328,6 +328,18 @@ public function from($address, $name = null)
         return $this->setAddress($address, $name, 'from');
     }
 
+    /**
+     * Determine if the given recipient is set on the mailable.
+     *
+     * @param  object|array|string  $address
+     * @param  string|null  $name
+     * @return bool
+     */
+    public function hasFrom($address, $name = null)
+    {
+        return $this->hasRecipient($address, $name, 'from');
+    }
+
     /**
      * Set the recipients of the message.
      *