Improve the performance of the shielded sync ledger client (backport #4016) #1319

Job	Run time
build-binaries	10m 33s
changelog	17s
build-wasm (wasm, build-wasm-scripts, wasm/tx_.wasm wasm/vp_.wasm wasm/checksums.json )	4m 3s
check-packages	5m 21s
build-wasm (wasm-for-tests, build-wasm-tests-scripts, wasm_for_tests/*.wasm)	3m 16s
lints	6m 15s
rust-docs	7m 32s
test-integration	19m 49s
check-benchmarks	10m 20s
test-wasm	8m 8s
test-unit	11m 4s
test-e2e-with-device-automation	9m 48s
test-e2e (0)	22m 46s
test-e2e (1)	21m 1s
test-e2e (2)	22m 31s
test-e2e (3)	22m 28s
test-e2e (4)	18m 18s
upload-coverage	10s
	3h 23m 40s

Provide feedback