Fix return type of SmrAccount::isDisabled
Fix return type of SmrAccount::isDisabled

Returns `array|false` instead of `bool`. This is now documented, but
cannot be implemented until PHP 8 where union types are introduced.

hemberger/smr,hemberger/smr,smrealms/smr,smrealms/smr,hemberger/smr,smrealms/smr,hemberger/smr