refactor: fix `missingType.return` errors in system files #13153

Job	Run time
Setup PHP Version for Code Coverage	2s
Others (8.2) / Sanity Tests	3m 42s
Others (8.1) / Sanity Tests	2m 31s
Others (8.3) / Sanity Tests	2m 37s
Others (8.4) / Sanity Tests	2m 32s
SeparateProcess (8.1) / tests	3m 32s
SeparateProcess (8.2) / tests	3m 29s
SeparateProcess (8.3) / tests	3m 22s
DatabaseLive (8.1, SQLite3, 8.0) / tests	2m 50s
SeparateProcess (8.4) / tests	3m 15s
DatabaseLive (8.2, MySQLi, 8.0) / tests	5m 58s
DatabaseLive (8.3, OCI8, 8.0) / tests	5m 59s
DatabaseLive (8.4, SQLSRV, 8.0) / tests	5m 6s
DatabaseLive (8.4, MySQLi, 8.0) / tests	6m 12s
DatabaseLive (8.1, MySQLi, 8.0) / tests	5m 56s
DatabaseLive (8.1, SQLSRV, 8.0) / tests	4m 57s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	5m 34s
DatabaseLive (8.1, MySQLi, 5.7) / tests	3m 24s
DatabaseLive (8.4, Postgre, 8.0) / tests	2m 27s
DatabaseLive (8.4, SQLite3, 8.0) / tests	2m 51s
DatabaseLive (8.4, OCI8, 8.0) / tests	5m 51s
DatabaseLive (8.1, OCI8, 8.0) / tests	6m 5s
DatabaseLive (8.2, OCI8, 8.0) / tests	7m 43s
DatabaseLive (8.2, SQLite3, 8.0) / tests	3m 24s
DatabaseLive (8.1, Postgre, 8.0) / tests	2m 32s
DatabaseLive (8.3, MySQLi, 8.0) / tests	5m 49s
DatabaseLive (8.3, Postgre, 8.0) / tests	2m 42s
CacheLive (8.1) / Cache Live Tests	2m 16s
DatabaseLive (8.2, Postgre, 8.0) / tests	3m 12s
CacheLive (8.4) / Cache Live Tests	2m 14s
DatabaseLive (8.3, SQLite3, 8.0) / tests	2m 31s
CacheLive (8.2) / Cache Live Tests	2m 12s
CacheLive (8.3) / Cache Live Tests	2m 9s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	5m 29s
Upload coverage results to Coveralls / coveralls	37s
	2h 11m 2s

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