bug #10612 [Debug] Always ignore error_reporting value

Discussion
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[Debug] Always ignore error_reporting value

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | no
| Fixed tickets | symfony/symfony#10612
| License       | MIT
| Doc PR        | no