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/Requests/UserFormRequest.php

@@ -55,7 +55,7 @@ abstract class UserFormRequest extends \Illuminate\Foundation\Http\FormRequest
             're_fillable' => 'boolean',
             're_fill_button_text' => 'string|min:1|max:50',
             'submitted_text' => 'string|max:2000',
-            'redirect_url' => 'nullable|max:255',
+            'redirect_url' => 'nullable|string',
             'database_fields_update' => 'nullable|array',
             'max_submissions_count' => 'integer|nullable|min:1',
             'max_submissions_reached_text' => 'string|nullable',