minor symfony#61784 [Security] make test forward compatible (xabbuh)

This PR was merged into the 7.4 branch.

Discussion
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[Security] make test forward compatible

| Q             | A
| ------------- | ---
| Branch?       | 7.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        |
| License       | MIT

see the high deps failure in symfony#61760

Commits
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e978c2e make test forward compatible

Author: xabbuh

src/Symfony/Component/Security/Http/Tests/RememberMe/PersistentRememberMeHandlerTest.php

@@ -115,7 +115,7 @@ public function testConsumeRememberMeCookieValid()
         $rememberParts = explode(':', $rememberMeDetails->toString(), 4);
         $cookieParts = explode(':', $cookie->getValue(), 4);
 
-        $this->assertSame($rememberParts[0], $cookieParts[0]); // class
+        $this->assertSame(method_exists(PersistentToken::class, 'getClass') ? $rememberParts[0] : '', $cookieParts[0]); // class
         $this->assertSame($rememberParts[1], $cookieParts[1]); // identifier
         $this->assertEqualsWithDelta($lastUsed->getTimestamp() + 31536000, (int) $cookieParts[2], 2); // expire
         $this->assertNotSame($rememberParts[3], $cookieParts[3]); // value