Update dependency phpunit/phpunit to ^11.5.6 #2754

Job	Run time
Static Analysis by Psalm (locked, 8.3, ubuntu-latest)	12s
Static Analysis by PHPStan (locked, 8.2, ubuntu-latest)	13s
PHPUnit tests (lowest, 8.2, ubuntu-latest)	1s
Static Analysis by PHPStan (locked, 8.3, ubuntu-latest)	11s
PHPUnit tests (lowest, 8.2, windows-latest)	1s
Static Analysis by PHPStan (locked, 8.4, ubuntu-latest)	11s
PHPUnit tests (lowest, 8.3, ubuntu-latest)	1s
Check Backward Compatibility (locked, 8.4, ubuntu-latest)	15s
PHPUnit tests (lowest, 8.3, windows-latest)	1s
PHPUnit tests (lowest, 8.4, ubuntu-latest)	1s
Run benchmarks (locked, 8.4, ubuntu-latest)	19s
PHPUnit tests (lowest, 8.4, windows-latest)	1s
Check Coding Standards (locked, 8.2, ubuntu-latest)	7s
PHPUnit tests (highest, 8.2, ubuntu-latest)	14s
Run benchmarks (locked, 8.4, windows-latest)	16s
PHPUnit tests (highest, 8.2, windows-latest)	18s
PHPUnit tests (highest, 8.3, ubuntu-latest)	16s
PHPUnit tests (highest, 8.3, windows-latest)	12s
Test Compatibility (locked, 8.4, ubuntu-latest)	11s
PHPUnit tests (highest, 8.4, ubuntu-latest)	13s
Check Demo Scripts (locked, 8.4, ubuntu-latest)	10s
Test Compatibility (locked, 8.4, windows-latest)	1s
PHPUnit tests (highest, 8.4, windows-latest)	7s
PHPUnit tests (locked, 8.2, ubuntu-latest)	8s
Mutation tests (locked, 8.3, ubuntu-latest)	12s
PHPUnit tests (locked, 8.2, windows-latest)	9s
PHPUnit tests (locked, 8.3, ubuntu-latest)	13s
PHPUnit tests (locked, 8.3, windows-latest)	7s
PHPUnit tests (locked, 8.4, ubuntu-latest)	3s
PHPUnit tests (locked, 8.4, windows-latest)	1s
	4m 25s

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