Add `ExtractableAsset` trait for accessing extractable data #51017

Job	Run time
build-without-default-features	0s
build-without-default-features-status	0s
check-unused-dependencies	-1s
check-example-showcase-patches-still-work	-6s
run-examples-on-wasm	-6s
build-android	-8s
build-and-install-on-iOS	-10s
	-31s

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