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/tests/Feature/Forms/RedirectUrlLengthTest.php

@@ -0,0 +1,29 @@
+<?php
+
+test('form accepts long redirect urls', function () {
+    $this->withoutExceptionHandling();
+    $user = $this->actingAsUser();
+    $workspace = $this->createUserWorkspace($user);
+    $form = $this->createForm($user, $workspace);
+
+    // Create a very long URL (more than 255 characters)
+    $longUrl = 'https://example.com/?' . str_repeat('very-long-parameter=value&', 50);
+
+    $this->putJson(route('open.forms.update', $form->id), array_merge($form->toArray(), [
+        'redirect_url' => $longUrl
+    ]))->assertStatus(200);
+
+    expect($form->fresh()->redirect_url)->toBe($longUrl);
+});
+
+test('form accepts null redirect url', function () {
+    $user = $this->actingAsUser();
+    $workspace = $this->createUserWorkspace($user);
+    $form = $this->createForm($user, $workspace);
+
+    $this->putJson(route('open.forms.update', $form->id), array_merge($form->toArray(), [
+        'redirect_url' => null
+    ]))->assertStatus(200);
+
+    expect($form->fresh()->redirect_url)->toBeNull();
+});