Add extension storage scalar function #4147

Job	Run time
Rust publish dry-run	28s
check-java-publish-build (x86_64-unknown-linux-gnu, runs-on=27965634142/runner=amd64-medium/image...	1m 24s
Compat check / compat-test	5m 36s
Python (wheel build)	5m 25s
check-java-publish-build (aarch64-unknown-linux-gnu, runs-on=27965634142/runner=arm64-medium/imag...	1m 55s
	14m 48s

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