refactor: remove deprecated `BaseHandler::RESERVED_CHARACTERS` consta… #14418

Job	Run time
Setup PHP Version for Code Coverage	4s
Others (8.4) / Sanity Tests	2m 31s
Others (8.2) / Sanity Tests	4m 8s
Others (8.3) / Sanity Tests	2m 35s
Others (8.5) / Sanity Tests	5m 55s
SeparateProcess (8.5) / tests	3m 40s
CacheLive (8.4) / Cache Live Tests	2m 12s
CacheLive (8.5) / Cache Live Tests	2m 16s
DatabaseLive (8.4, SQLSRV, 8.0) / tests	5m 17s
SeparateProcess (8.3) / tests	3m 45s
CacheLive (8.3) / Cache Live Tests	2m 11s
DatabaseLive (8.2, MySQLi, 8.0) / tests	4m 48s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	5m 38s
SeparateProcess (8.4) / tests	3m 53s
SeparateProcess (8.2) / tests	3m 21s
DatabaseLive (8.4, OCI8, 8.0) / tests	7m 12s
CacheLive (8.2) / Cache Live Tests	2m 24s
DatabaseLive (8.5, OCI8, 8.0) / tests	6m 21s
DatabaseLive (8.2, Postgre, 8.0) / tests	3m 36s
DatabaseLive (8.3, OCI8, 8.0) / tests	7m 6s
DatabaseLive (8.3, SQLite3, 8.0) / tests	2m 21s
DatabaseLive (8.3, MySQLi, 8.0) / tests	4m 38s
DatabaseLive (8.5, Postgre, 8.0) / tests	2m 57s
DatabaseLive (8.2, SQLite3, 8.0) / tests	2m 55s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	6m 24s
DatabaseLive (8.2, OCI8, 8.0) / tests	7m 41s
DatabaseLive (8.5, SQLSRV, 8.0) / tests	5m 47s
DatabaseLive (8.4, Postgre, 8.0) / tests	2m 32s
DatabaseLive (8.4, MySQLi, 8.0) / tests	5m 2s
DatabaseLive (8.3, Postgre, 8.0) / tests	2m 40s
DatabaseLive (8.5, MySQLi, 8.0) / tests	4m 56s
DatabaseLive (8.2, MySQLi, 5.7) / tests	4m 1s
DatabaseLive (8.5, SQLite3, 8.0) / tests	2m 20s
DatabaseLive (8.4, SQLite3, 8.0) / tests	2m 29s
Upload coverage results to Coveralls / coveralls	48s
	2h 16m 24s

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