fix: prioritize headers set by the `Response` class #12369

Job	Run time
Setup PHP Version for Code Coverage	1s
Others (8.1) / Sanity Tests	2m 34s
Others (8.3) / Sanity Tests	2m 33s
Others (8.2) / Sanity Tests	3m 46s
Others (8.4, --ignore-platform-req=php) / Sanity Tests	2m 22s
CacheLive (8.2) / Cache Live Tests	2m 22s
CacheLive (8.1) / Cache Live Tests	1m 56s
CacheLive (8.4, --ignore-platform-req=php) / Cache Live Tests	2m 10s
CacheLive (8.3) / Cache Live Tests	2m 8s
SeparateProcess (8.1) / tests	3m 15s
SeparateProcess (8.2) / tests	3m 20s
SeparateProcess (8.3) / tests	3m 17s
DatabaseLive (8.1, MySQLi, 5.7) / tests	2m 57s
DatabaseLive (8.1, MySQLi, 8.0) / tests	3m 42s
DatabaseLive (8.1, OCI8, 8.0) / tests	5m 44s
SeparateProcess (8.4, --ignore-platform-req=php) / tests	3m 9s
DatabaseLive (8.1, Postgre, 8.0) / tests	2m 22s
DatabaseLive (8.1, SQLite3, 8.0) / tests	2m 43s
DatabaseLive (8.1, SQLSRV, 8.0) / tests	4m 17s
DatabaseLive (8.2, MySQLi, 8.0) / tests	5m 9s
DatabaseLive (8.2, OCI8, 8.0) / tests	6m 13s
DatabaseLive (8.2, Postgre, 8.0) / tests	2m 58s
DatabaseLive (8.2, SQLite3, 8.0) / tests	3m 20s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	5m 6s
DatabaseLive (8.3, MySQLi, 8.0) / tests	3m 45s
DatabaseLive (8.3, OCI8, 8.0) / tests	5m 56s
DatabaseLive (8.3, Postgre, 8.0) / tests	2m 27s
DatabaseLive (8.3, SQLite3, 8.0) / tests	2m 30s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	3m 49s
DatabaseLive (8.4, --ignore-platform-req=php) / tests	2m 7s
Upload coverage results to Coveralls / coveralls	49s
	1h 38m 47s

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