clippy: Replaces .get(0) with .first() (#34150) #17

Job	Run time
cargo-test-sbf (token/program)	7m 25s
cargo-test-sbf (instruction-padding/program, token/program-2022, token/program-2022-test)	11m 18s
check	0s
test	0s
cargo-test-sbf (associated-token-account/program, associated-token-account/program-test)	7m 34s
cargo-test-sbf (token-upgrade/program)	5m 57s
cargo-test-sbf (feature-proposal/program)	6m 8s
cargo-test-sbf (governance/addin-mock/program, governance/program)	10m 20s
cargo-test-sbf (memo/program)	7m 12s
cargo-test-sbf (name-service/program)	5m 59s
cargo-test-sbf (stake-pool/program)	10m 19s
cargo-test-sbf (single-pool/program)	7m 47s
	1h 19m 59s

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