zcash_client_backend: Remove deprecated and duplicative wallet APIs. #5978

Job	Run time
Test on Linux	9m 2s
Test Orchard on Linux	10m 56s
Bitrot check	1m 32s
Latest build on ubuntu-latest	2m 13s
Test NU6 on Linux	8m 57s
Check ZFuture build on Linux	30s
Latest build on windows-latest	3m 40s
Test on macOS	13m 7s
Check ZFuture build on macOS	40s
Clippy (MSRV)	1m 14s
Test Orchard on macOS	18m 28s
Latest build on macOS-latest	2m 32s
Check ZFuture build on Windows	2m 39s
Test on Windows	16m 12s
Test Orchard on Windows	19m 25s
Clippy (beta)	14s
Test NU6 on Windows	17m 15s
Code coverage	58m 43s
Intra-doc links	2m 9s
Build target wasm32-wasi	55s
Rustfmt	13s
protobuf consistency	1m 2s
UUID validity	3s
	3h 11m 41s

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