minor #30009 [MonologBridge] Remove unused local variable (samnela)

This PR was merged into the 4.1 branch.

Discussion
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[MonologBridge] Remove unused local variable

| Q             | A
| ------------- | ---
| Branch?       | 4.1
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

Commits
-------

5580473740 [MonologBridge] Remove unused local variable

src/Symfony/Bridge/Monolog/Handler/FingersCrossed/HttpCodeActivationStrategy.php

@@ -60,7 +60,6 @@ class HttpCodeActivationStrategy extends ErrorLevelActivationStrategy
                     continue;
                 }
 
-                $urlBlacklist = null;
                 if (\count($exclusion['urls'])) {
                     return !preg_match('{('.implode('|', $exclusion['urls']).')}i', $request->getPathInfo());
                 }