Sablier

Description: Certain functions fail to validate incoming arguments, so callers can accidentally set important state
variables like recipients and in Adminable::transferAdmin to the zero address. in ISablierV2LockupTranched.sol the
Requirements for createWithTimestamps(), createWithDurations() is "params.recipient must not be the zero address."
but there's no zero address checks, theres more functions need's to check if the value is zero address in v2-core and v2-priphery.

Impact:

• callers can accidentally set important parameters to zero address or value.

• The current admin transfer process involves the admin calling Adminable::transferAdmin(). This function doesn’t
  check the new admin is not the zero address and proceeds to write the new admin address into the admin state variable.
  If the nominated EOA account is not a valid account, it is entirely possible the admin may accidentally transfer the
  admin rule to an uncontrolled account, breaking all functions with the onlyAdmin() modifier.

Recommended Mitigation:

• add zero address checks like require() or if() statements on all function arguments to ensure that users cannot
  accidentally set incorrect values.