phpstan: remove ignoreErrors (not needed anymore with symfony 7) #33685

Job	Run time
Lint: API (php-cs-fixer)	33s
Tests: API	10m 30s
Lint: ClientPrint (ESLint)	16s
Lint: e2e (ESLint)	22s
Lint: Frontend (ESLint)	42s
Tests: Frontend	2m 30s
Lint: Print (ESLint)	28s
Tests: PDF	28s
Tests: Print	53s
Tests: End-to-end build / Tests: End-to-end (build job)	31s
Tests: End-to-end run / Tests: End-to-end (chrome)	4m 30s
Tests: End-to-end run / Tests: End-to-end (firefox)	4m 16s
Tests: End-to-end run / Tests: End-to-end (edge)	4m 50s
Finish coveralls report	5s
workflow-success	1s
Send out CI success event	0s
	30m 55s

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