The signer messaging may use for an account. A read-only account is signed
in but can neither sign nor decrypt, so it is offered without its
encryption methods and reports signer-cannot-encrypt.
Parameters
account: IAccount<ISigner,any,any>|undefined
The active account, if any.
Returns ISigner|undefined
The account itself, a signer without encryption for a read-only account, or undefined.
The signer messaging may use for an account. A read-only account is signed in but can neither sign nor decrypt, so it is offered without its encryption methods and reports
signer-cannot-encrypt.