[8.x] Remove illuminate/foundation dependency from Password validation

[netpok]

Currently the password validation rule uses the __ foundation helper function but the illuminate/validation package does not depend on the illuminate/foundation package.

This PR will make the rule use the Translator from the Validator.

The only problem is that in theory getTranslator is not part of the Validator interface, but this happens many places in the framework.

[driesvints]

Isn't this a breaking change? What if apps don't have the translator set and are already using the feature?

[netpok]

The Validator already depends on the translator, the __ helper also depends on the translator. Basically if no translator is set in the app it's already broken.

[driesvints]

Where are you calling setValidator?

[netpok]

It is called here:
https://github.com/laravel/framework/blob/8.x/src/Illuminate/Validation/Validator.php#L753

[driesvints]

@netpok perfect, thanks