Add additional check if password hash is empty in auth process

[rafczow]

Fixes #1067

Additional details about this PR

Same issue was found in core magento module and is described in this issue:
magento/magento2#19060
and solved here:
https://github.com/magento/magento2/pull/19066/files

My PR is copy of that solution

[jaybeckr]

Thanks for the fix! We have cherry picked the commit to be included in the next release.

@christianzichichi - please close this PR, ref internal ticket ASD-757

[rafczow]

@jaybeckr ive realized there is also translation function missing in that file, it is:
$this->messageManager->addErrorMessage('The password supplied was incorrect');
and should be:
$this->messageManager->addErrorMessage(__('The password supplied was incorrect'));

Should i create separate PR or can you add it internally? :)

[jaybeckr]

@rafczow - we have an internal ticket to review strings and get translations all updated, I will add the translation wrapper on this string which you can use to alter the messaging (and translate, of course) if desired. Thanks!