[NFC] Drop unnecessary `sycl.hpp` includes #3137

Job	Run time
check-clang-format	27s
check-secrets	3s
build-common-base-image	0s
build-image-for-sycl-impl	0s
compile-cts (adaptivecpp, 061e2d6ffe1084021d99f22ac1f16e28c6dab899)	1h 16m 5s
compile-cts (simsycl, 27ca7a05e65d24c784ba831225d0a53341719590)	55m 10s
compile-cts (dpcpp, 2025-05-01)	4h 57m 54s
cts-compiles-for-all-implementations	4s
	7h 9m 43s

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