Deprecate RpcClient::get_stake_activation #6564

Job	Run time
check	4m 12s
cargo-test-sbf (token/program)	10m 7s
test (token/cli, token/program, token/program-2022, associated-token-account/program, instruction...	21m 39s
cargo-test-sbf (instruction-padding/program, token/program-2022, token/program-2022-test)	15m 31s
test (single-pool/cli, single-pool/program)	21m 12s
cargo-test-sbf (associated-token-account/program, associated-token-account/program-test)	10m 13s
test (token-upgrade/cli, token-upgrade/program)	18m 1s
cargo-test-sbf (token-upgrade/program)	9m 48s
cargo-test-sbf (feature-proposal/program)	9m 43s
cargo-test-sbf (governance/addin-mock/program, governance/program)	13m 45s
cargo-test-sbf (memo/program)	8m 30s
cargo-test-sbf (name-service/program)	8m 30s
cargo-test-sbf (stake-pool/program)	13m 43s
cargo-test-sbf (single-pool/program)	9m 51s
	2h 54m 45s

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