Enhance redirect URL handling and MentionParser functionality (#639)

- Updated the `redirect_url` validation in `UserFormRequest` to accept strings instead of just max length.
- Modified `MentionParser` to include a `urlFriendlyOutput` method, allowing for URL encoding of special characters in parsed values.
- Adjusted the `PublicFormController` to utilize the new `urlFriendlyOutput` method for redirect URLs.
- Created a migration to change the `redirect_url` field type in the database from string to text, accommodating longer URLs.
- Added tests to ensure proper handling of long redirect URLs and the functionality of the new URL-friendly output feature in `MentionParser`.

This update improves the flexibility and robustness of form handling and URL processing.

api/app/Http/Controllers/Forms/PublicFormController.php

@@ -116,7 +116,7 @@ class PublicFormController extends Controller
             return ['id' => $key, 'value' => $value];
         })->values()->all();
 
-        $redirectUrl = ($form->redirect_url) ? (new MentionParser($form->redirect_url, $formattedData))->parseAsText() : null;
+        $redirectUrl = ($form->redirect_url) ? (new MentionParser($form->redirect_url, $formattedData))->urlFriendlyOutput()->parseAsText() : null;
 
         if ($redirectUrl && !filter_var($redirectUrl, FILTER_VALIDATE_URL)) {
             $redirectUrl = null;