fix: prioritize headers set by the `Response` class #12670

Job	Run time
Setup PHP Version for Code Coverage	1s
Others (8.4) / Sanity Tests	2m 22s
Others (8.2) / Sanity Tests	3m 50s
Others (8.1) / Sanity Tests	2m 29s
Others (8.3) / Sanity Tests	2m 35s
CacheLive (8.3) / Cache Live Tests	2m 0s
CacheLive (8.2) / Cache Live Tests	2m 27s
CacheLive (8.1) / Cache Live Tests	2m 7s
CacheLive (8.4) / Cache Live Tests	1m 54s
DatabaseLive (8.1, OCI8, 8.0) / tests	5m 49s
DatabaseLive (8.1, MySQLi, 5.7) / tests	3m 8s
DatabaseLive (8.1, MySQLi, 8.0) / tests	5m 2s
DatabaseLive (8.1, Postgre, 8.0) / tests	2m 37s
DatabaseLive (8.1, SQLite3, 8.0) / tests	2m 28s
DatabaseLive (8.2, MySQLi, 8.0) / tests	4m 44s
DatabaseLive (8.1, SQLSRV, 8.0) / tests	4m 17s
DatabaseLive (8.2, OCI8, 8.0) / tests	6m 20s
DatabaseLive (8.2, Postgre, 8.0) / tests	3m 11s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	5m 34s
DatabaseLive (8.2, SQLite3, 8.0) / tests	3m 30s
DatabaseLive (8.3, MySQLi, 8.0) / tests	4m 46s
DatabaseLive (8.3, OCI8, 8.0) / tests	6m 11s
DatabaseLive (8.3, Postgre, 8.0) / tests	2m 27s
DatabaseLive (8.3, SQLite3, 8.0) / tests	2m 25s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	4m 6s
DatabaseLive (8.4, MySQLi, 8.0) / tests	4m 59s
DatabaseLive (8.4, OCI8, 8.0) / tests	6m 27s
DatabaseLive (8.4, Postgre, 8.0) / tests	2m 37s
DatabaseLive (8.4, SQLite3, 8.0) / tests	2m 17s
DatabaseLive (8.4, SQLSRV, 8.0) / tests	4m 3s
SeparateProcess (8.1) / tests	3m 5s
SeparateProcess (8.2) / tests	3m 23s
SeparateProcess (8.3) / tests	3m 20s
SeparateProcess (8.4) / tests	3m 15s
Upload coverage results to Coveralls / coveralls	45s
	2h 0m 31s

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