fet(hbar): add AccountUpdate support to explainTransaction in BitGoJS

[aditya-bitgo]

ticket: SI-511

[linear-code]

SI-511 [BitgoJS] add AccountUpdate support to explainTransaction in BitGoJS

[Doddanna17]

Fix is correct and necessary. Without the cryptoUpdateAccount case, verifyTransaction throws for all staking ops since explainTransaction is called internally for every transaction type.

Two notes: (1) PR title typo — fet(hbar) → feat(hbar). (2) Unstake test is missing id, timestamp, memo assertions that the stake test has — inconsistency could mask regressions.

LGTM.

[Doddanna17]

Fix is correct and necessary. Without the cryptoUpdateAccount case, verifyTransaction throws for all staking ops since explainTransaction is called internally for every transaction type.

Two notes: (1) PR title typo — fet(hbar) → feat(hbar). (2) Unstake test is missing id, timestamp, memo assertions that the stake test has — inconsistency could mask regressions.

LGTM.